curl_easy_setopt(3) - phpMan

curl_easy_setopt(3) libcurl Manual curl_easy_setopt(3)

NAME
curl_easy_setopt - set options for a curl easy handle

SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLoption option, parameter);

DESCRIPTION
curl_easy_setopt() is used to tell libcurl how to behave. By using the appropriate options
to curl_easy_setopt, you can change libcurl's behavior. All options are set with the
option followed by a parameter. That parameter can be a long, a function pointer, an
object pointer or a curl_off_t, depending on what the specific option expects. Read this
manual carefully as bad input values may cause libcurl to behave badly! You can only set
one option in each function call. A typical application uses many curl_easy_setopt() calls
in the setup phase.

Options set with this function call are valid for all forthcoming transfers performed
using this handle. The options are not in any way reset between transfers, so if you want
subsequent transfers with different options, you must change them between the transfers.
You can optionally reset all options back to internal default with curl_easy_reset(3).

Strings passed to libcurl as 'char *' arguments, are copied by the library; thus the
string storage associated to the pointer argument may be overwritten after
curl_easy_setopt() returns. Exceptions to this rule are described in the option details
below.

NOTE: before 7.17.0 strings were not copied. Instead the user was forced keep them avail-
able until libcurl no longer needed them.

The handle is the return code from a curl_easy_init(3) or curl_easy_duphandle(3) call.

BEHAVIOR OPTIONS
CURLOPT_VERBOSE
Set the parameter to non-zero to get the library to display a lot of verbose infor-
mation about its operations. Very useful for libcurl and/or protocol debugging and
understanding. The verbose information will be sent to stderr, or the stream set
with CURLOPT_STDERR.

You hardly ever want this set in production use, you will almost always want this
when you debug/report problems. Another neat option for debugging is the CUR-
LOPT_DEBUGFUNCTION.

CURLOPT_HEADER
A non-zero parameter tells the library to include the header in the body output.
This is only relevant for protocols that actually have headers preceding the data
(like HTTP).

CURLOPT_NOPROGRESS
A non-zero parameter tells the library to shut off the built-in progress meter com-
pletely.

Future versions of libcurl is likely to not have any built-in progress meter at
all.

CURLOPT_NOSIGNAL
Pass a long. If it is non-zero, libcurl will not use any functions that install
signal handlers or any functions that cause signals to be sent to the process. This
option is mainly here to allow multi-threaded unix applications to still set/use
all timeout options etc, without risking getting signals. (Added in 7.10)

Consider building libcurl with ares support to enable asynchronous DNS lookups. It
enables nice timeouts for name resolves without signals.

CALLBACK OPTIONS
CURLOPT_WRITEFUNCTION
Function pointer that should match the following prototype: size_t function( void
*ptr, size_t size, size_t nmemb, void *stream); This function gets called by
libcurl as soon as there is data received that needs to be saved. The size of the
data pointed to by ptr is size multiplied with nmemb, it will not be zero termi-
nated. Return the number of bytes actually taken care of. If that amount differs
from the amount passed to your function, it'll signal an error to the library and
it will abort the transfer and return CURLE_WRITE_ERROR.

From 7.18.0, the function can return CURL_WRITEFUNC_PAUSE which then will cause
writing to this connection to become paused. See curl_easy_pause(3) for further
details.

This function may be called with zero bytes data if the transfered file is empty.

Set this option to NULL to get the internal default function. The internal default
function will write the data to the FILE * given with CURLOPT_WRITEDATA.

Set the stream argument with the CURLOPT_WRITEDATA option.

The callback function will be passed as much data as possible in all invokes, but
you cannot possibly make any assumptions. It may be one byte, it may be thousands.
The maximum amount of data that can be passed to the write callback is defined in
the curl.h header file: CURL_MAX_WRITE_SIZE.

CURLOPT_WRITEDATA
Data pointer to pass to the file write function. If you use the CURLOPT_WRITEFUNC-
TION option, this is the pointer you'll get as input. If you don't use a callback,
you must pass a 'FILE *' as libcurl will pass this to fwrite() when writing data.

The internal CURLOPT_WRITEFUNCTION will write the data to the FILE * given with
this option, or to stdout if this option hasn't been set.

If you're using libcurl as a win32 DLL, you MUST use the CURLOPT_WRITEFUNCTION if
you set this option or you will experience crashes.

This option is also known with the older name CURLOPT_FILE, the name CURLOPT_WRITE-
DATA was introduced in 7.9.7.

CURLOPT_READFUNCTION
Function pointer that should match the following prototype: size_t function( void
*ptr, size_t size, size_t nmemb, void *stream); This function gets called by
libcurl as soon as it needs to read data in order to send it to the peer. The data
area pointed at by the pointer ptr may be filled with at most size multiplied with
nmemb number of bytes. Your function must return the actual number of bytes that
you stored in that memory area. Returning 0 will signal end-of-file to the library
and cause it to stop the current transfer.

If you stop the current transfer by returning 0 "pre-maturely" (i.e before the
server expected it, like when you've told you will upload N bytes and you upload
less than N bytes), you may experience that the server "hangs" waiting for the rest
of the data that won't come.

The read callback may return CURL_READFUNC_ABORT to stop the current operation
immediately, resulting in a CURLE_ABORTED_BY_CALLBACK error code from the transfer
(Added in 7.12.1)

From 7.18.0, the function can return CURL_READFUNC_PAUSE which then will cause
reading from this connection to become paused. See curl_easy_pause(3) for further
details.

If you set the callback pointer to NULL, or doesn't set it at all, the default
internal read function will be used. It is simply doing an fread() on the FILE *
stream set with CURLOPT_READDATA.

CURLOPT_READDATA
Data pointer to pass to the file read function. If you use the CURLOPT_READFUNCTION
option, this is the pointer you'll get as input. If you don't specify a read call-
back but instead rely on the default internal read function, this data must be a
valid readable FILE *.

If you're using libcurl as a win32 DLL, you MUST use a CURLOPT_READFUNCTION if you
set this option.

This option is also known with the older name CURLOPT_INFILE, the name CUR-
LOPT_READDATA was introduced in 7.9.7.

CURLOPT_IOCTLFUNCTION
Function pointer that should match the curl_ioctl_callback prototype found in
<curl/curl.h>. This function gets called by libcurl when something special I/O-
related needs to be done that the library can't do by itself. For now, rewinding
the read data stream is the only action it can request. The rewinding of the read
data stream may be necessary when doing a HTTP PUT or POST with a multi-pass
authentication method. (Option added in 7.12.3).

Use CURLOPT_SEEKFUNCTION instead to provide seeking!

CURLOPT_IOCTLDATA
Pass a pointer that will be untouched by libcurl and passed as the 3rd argument in
the ioctl callback set with CURLOPT_IOCTLFUNCTION. (Option added in 7.12.3)

CURLOPT_SEEKFUNCTION
Function pointer that should match the following prototype: int function(void
*instream, curl_off_t offset, int origin); This function gets called by libcurl to
seek to a certain position in the input stream and can be used to fast forward a
file in a resumed upload (instead of reading all uploaded bytes with the normal
read function/callback). It is also called to rewind a stream when doing a HTTP PUT
or POST with a multi-pass authentication method. The function shall work like
"fseek" or "lseek" and accepted SEEK_SET, SEEK_CUR and SEEK_END as argument for
origin, although (in 7.18.0) libcurl only passes SEEK_SET. The callback must return
0 on success as returning non-zero will cause the upload operation to fail.

If you forward the input arguments directly to "fseek" or "lseek", note that the
data type for offset is not the same as defined for curl_off_t on many systems!
(Option added in 7.18.0)

CURLOPT_SEEKDATA
Data pointer to pass to the file read function. If you use the CURLOPT_SEEKFUNCTION
option, this is the pointer you'll get as input. If you don't specify a seek call-
back, NULL is passed. (Option added in 7.18.0)

CURLOPT_SOCKOPTFUNCTION
Function pointer that should match the curl_sockopt_callback prototype found in
<curl/curl.h>. This function gets called by libcurl after the socket() call but
before the connect() call. The callback's purpose argument identifies the exact
purpose for this particular socket, and currently only one value is supported:
CURLSOCKTYPE_IPCXN for the primary connection (meaning the control connection in
the FTP case). Future versions of libcurl may support more purposes. It passes the
newly created socket descriptor so additional setsockopt() calls can be done at the
user's discretion. A non-zero return code from the callback function will signal
an unrecoverable error to the library and it will close the socket and return
CURLE_COULDNT_CONNECT. (Option added in 7.15.6.)

CURLOPT_SOCKOPTDATA
Pass a pointer that will be untouched by libcurl and passed as the first argument
in the sockopt callback set with CURLOPT_SOCKOPTFUNCTION. (Option added in
7.15.6.)

CURLOPT_OPENSOCKETFUNCTION
Function pointer that should match the curl_opensocket_callback prototype found in
<curl/curl.h>. This function gets called by libcurl instead of the socket(2) call.
The callback's purpose argument identifies the exact purpose for this particular
socket, and currently only one value is supported: CURLSOCKTYPE_IPCXN for the pri-
mary connection (meaning the control connection in the FTP case). Future versions
of libcurl may support more purposes. It passes the resolved peer address as a
address argument so the callback can modify the address or refuse to connect at
all. The callback function should return the socket or CURL_SOCKET_BAD in case no
connection should be established or any error detected. Any additional setsock-
opt(2) calls can be done on the socket at the user's discretion. CURL_SOCKET_BAD
return value from the callback function will signal an unrecoverable error to the
library and it will return CURLE_COULDNT_CONNECT. This return code can be used for
IP address blacklisting. The default behavior is:
return socket(addr->family, addr->socktype, addr->protocol); (Option added in
7.17.1.)

CURLOPT_OPENSOCKETDATA
Pass a pointer that will be untouched by libcurl and passed as the first argument
in the opensocket callback set with CURLOPT_OPENSOCKETFUNCTION. (Option added in
7.17.1.)

CURLOPT_PROGRESSFUNCTION
Function pointer that should match the curl_progress_callback prototype found in
<curl/curl.h>. This function gets called by libcurl instead of its internal equiva-
lent with a frequent interval during operation (roughly once per second) no matter
if data is being transfered or not. Unknown/unused argument values passed to the
callback will be set to zero (like if you only download data, the upload size will
remain 0). Returning a non-zero value from this callback will cause libcurl to
abort the transfer and return CURLE_ABORTED_BY_CALLBACK.

If you transfer data with the multi interface, this function will not be called
during periods of idleness unless you call the appropriate libcurl function that
performs transfers.

CURLOPT_NOPROGRESS must be set to FALSE to make this function actually get called.

CURLOPT_PROGRESSDATA
Pass a pointer that will be untouched by libcurl and passed as the first argument
in the progress callback set with CURLOPT_PROGRESSFUNCTION.

CURLOPT_HEADERFUNCTION
Function pointer that should match the following prototype: size_t function( void
*ptr, size_t size, size_t nmemb, void *stream);. This function gets called by
libcurl as soon as it has received header data. The header callback will be called
once for each header and only complete header lines are passed on to the callback.
Parsing headers should be easy enough using this. The size of the data pointed to
by ptr is size multiplied with nmemb. Do not assume that the header line is zero
terminated! The pointer named stream is the one you set with the CURLOPT_WRITE-
HEADER option. The callback function must return the number of bytes actually taken
care of, or return -1 to signal error to the library (it will cause it to abort the
transfer with a CURLE_WRITE_ERROR return code).

If this option is not set, or if it is set to NULL, but CURLOPT_HEADERDATA (CUR-
LOPT_WRITEHEADER) is set to anything but NULL, the function used to accept response
data will be used instead. That is, it will be the function specified with CUR-
LOPT_WRITEFUNCTION, or if it is not specified or NULL - the default, stream-writing
function.

Since 7.14.1: When a server sends a chunked encoded transfer, it may contain a
trailer. That trailer is identical to a HTTP header and if such a trailer is
received it is passed to the application using this callback as well. There are
several ways to detect it being a trailer and not an ordinary header: 1) it comes
after the response-body. 2) it comes after the final header line (CR LF) 3) a
Trailer: header among the response-headers mention what header to expect in the
trailer.

CURLOPT_WRITEHEADER
(This option is also known as CURLOPT_HEADERDATA) Pass a pointer to be used to
write the header part of the received data to. If you don't use your own callback
to take care of the writing, this must be a valid FILE *. See also the CUR-
LOPT_HEADERFUNCTION option above on how to set a custom get-all-headers callback.

CURLOPT_DEBUGFUNCTION
Function pointer that should match the following prototype: int curl_debug_callback
(CURL *, curl_infotype, char *, size_t, void *); CURLOPT_DEBUGFUNCTION replaces the
standard debug function used when CURLOPT_VERBOSE is in effect. This callback
receives debug information, as specified with the curl_infotype argument. This
function must return 0. The data pointed to by the char * passed to this function
WILL NOT be zero terminated, but will be exactly of the size as told by the size_t
argument.

Available curl_infotype values:

CURLINFO_TEXT
The data is informational text.

CURLINFO_HEADER_IN
The data is header (or header-like) data received from the peer.

CURLINFO_HEADER_OUT
The data is header (or header-like) data sent to the peer.

CURLINFO_DATA_IN
The data is protocol data received from the peer.

CURLINFO_DATA_OUT
The data is protocol data sent to the peer.

CURLOPT_DEBUGDATA
Pass a pointer to whatever you want passed in to your CURLOPT_DEBUGFUNCTION in the
last void * argument. This pointer is not used by libcurl, it is only passed to the
callback.

CURLOPT_SSL_CTX_FUNCTION
This option does only function for libcurl powered by OpenSSL. If libcurl was built
against another SSL library, this functionality is absent.

Function pointer that should match the following prototype: CURLcode sslctxfun(CURL
*curl, void *sslctx, void *parm); This function gets called by libcurl just before
the initialization of an SSL connection after having processed all other SSL
related options to give a last chance to an application to modify the behaviour of
openssl's ssl initialization. The sslctx parameter is actually a pointer to an
openssl SSL_CTX. If an error is returned no attempt to establish a connection is
made and the perform operation will return the error code from this callback func-
tion. Set the parm argument with the CURLOPT_SSL_CTX_DATA option. This option was
introduced in 7.11.0.

This function will get called on all new connections made to a server, during the
SSL negotiation. The SSL_CTX pointer will be a new one every time.

To use this properly, a non-trivial amount of knowledge of the openssl libraries is
necessary. Using this function allows for example to use openssl callbacks to add
additional validation code for certificates, and even to change the actual URI of
an HTTPS request (example used in the lib509 test case). See also the example sec-
tion for a replacement of the key, certificate and trust file settings.

CURLOPT_SSL_CTX_DATA
Data pointer to pass to the ssl context callback set by the option CUR-
LOPT_SSL_CTX_FUNCTION, this is the pointer you'll get as third parameter, otherwise
NULL. (Added in 7.11.0)

CURLOPT_CONV_TO_NETWORK_FUNCTION

CURLOPT_CONV_FROM_NETWORK_FUNCTION

CURLOPT_CONV_FROM_UTF8_FUNCTION
Function pointers that should match the following prototype: CURLcode function(char
*ptr, size_t length);

These three options apply to non-ASCII platforms only. They are available only if
CURL_DOES_CONVERSIONS was defined when libcurl was built. When this is the case,
curl_version_info(3) will return the CURL_VERSION_CONV feature bit set.

The data to be converted is in a buffer pointed to by the ptr parameter. The
amount of data to convert is indicated by the length parameter. The converted data
overlays the input data in the buffer pointed to by the ptr parameter. CURLE_OK
should be returned upon successful conversion. A CURLcode return value defined by
curl.h, such as CURLE_CONV_FAILED, should be returned if an error was encountered.

CURLOPT_CONV_TO_NETWORK_FUNCTION and CURLOPT_CONV_FROM_NETWORK_FUNCTION convert
between the host encoding and the network encoding. They are used when commands or
ASCII data are sent/received over the network.

CURLOPT_CONV_FROM_UTF8_FUNCTION is called to convert from UTF8 into the host encod-
ing. It is required only for SSL processing.

If you set a callback pointer to NULL, or don't set it at all, the built-in libcurl
iconv functions will be used. If HAVE_ICONV was not defined when libcurl was
built, and no callback has been established, conversion will return the
CURLE_CONV_REQD error code.

If HAVE_ICONV is defined, CURL_ICONV_CODESET_OF_HOST must also be defined. For
example:

#define CURL_ICONV_CODESET_OF_HOST "IBM-1047"

The iconv code in libcurl will default the network and UTF8 codeset names as fol-
lows:

#define CURL_ICONV_CODESET_OF_NETWORK "ISO8859-1"

#define CURL_ICONV_CODESET_FOR_UTF8 "UTF-8"

You will need to override these definitions if they are different on your system.

ERROR OPTIONS
CURLOPT_ERRORBUFFER
Pass a char * to a buffer that the libcurl may store human readable error messages
in. This may be more helpful than just the return code from curl_easy_perform. The
buffer must be at least CURL_ERROR_SIZE big. Although this argument is a 'char *',
it does not describe an input string. Therefore the (probably undefined) contents
of the buffer is NOT copied by the library. You should keep the associated storage
available until libcurl no longer needs it. Failing to do so will cause very odd
behavior or even crashes. libcurl will need it until you call curl_easy_cleanup(3)
or you set the same option again to use a different pointer.

Use CURLOPT_VERBOSE and CURLOPT_DEBUGFUNCTION to better debug/trace why errors hap-
pen.

If the library does not return an error, the buffer may not have been touched. Do
not rely on the contents in those cases.

CURLOPT_STDERR
Pass a FILE * as parameter. Tell libcurl to use this stream instead of stderr when
showing the progress meter and displaying CURLOPT_VERBOSE data.

CURLOPT_FAILONERROR
A non-zero parameter tells the library to fail silently if the HTTP code returned
is equal to or larger than 400. The default action would be to return the page nor-
mally, ignoring that code.

This method is not fail-safe and there are occasions where non-successful response
codes will slip through, especially when authentication is involved (response codes
401 and 407).

You might get some amounts of headers transferred before this situation is
detected, like for when a "100-continue" is received as a response to a POST/PUT
and a 401 or 407 is received immediately afterwards.

NETWORK OPTIONS
CURLOPT_URL
The actual URL to deal with. The parameter should be a char * to a zero terminated
string.

If the given URL lacks the protocol part ("http://" or "ftp://" etc), it will
attempt to guess which protocol to use based on the given host name. If the given
protocol of the set URL is not supported, libcurl will return on error
(CURLE_UNSUPPORTED_PROTOCOL) when you call curl_easy_perform(3) or curl_multi_per-
form(3). Use curl_version_info(3) for detailed info on which protocols that are
supported.

The string given to CURLOPT_URL must be url-encoded and following the RFC 2396
(http://curl.haxx.se/rfc/rfc2396.txt).

CURLOPT_URL is the only option that must be set before curl_easy_perform(3) is
called.

CURLOPT_PROTOCOLS can be used to limit what protocols libcurl will use for this
transfer, independent of what libcurl has been compiled to support. That may be
useful if you accept the URL from an external source and want to limit the accessi-
bility.

CURLOPT_PROTOCOLS
Pass a long that holds a bitmask of CURLPROTO_* defines. If used, this bitmask lim-
its what protocols libcurl may use in the transfer. This allows you to have a
libcurl built to support a wide range of protocols but still limit specific trans-
fers to only be allowed to use a subset of them. By default libcurl will accept all
protocols it supports. See also CURLOPT_REDIR_PROTOCOLS. (Added in 7.19.4)

CURLOPT_REDIR_PROTOCOLS
Pass a long that holds a bitmask of CURLPROTO_* defines. If used, this bitmask lim-
its what protocols libcurl may use in a transfer that it follows to in a redirect
when CURLOPT_FOLLOWLOCATION is enabled. This allows you to limit specific transfers
to only be allowed to use a subset of protocols in redirections. By default libcurl
will allow all protocols except for FILE and SCP. This is a difference compared to
pre-7.19.4 versions which unconditionally would follow to all protocols supported.
(Added in 7.19.4)

CURLOPT_PROXY
Set HTTP proxy to use. The parameter should be a char * to a zero terminated string
holding the host name or dotted IP address. To specify port number in this string,
append :[port] to the end of the host name. The proxy string may be prefixed with
[protocol]:// since any such prefix will be ignored. The proxy's port number may
optionally be specified with the separate option CURLOPT_PROXYPORT.

When you tell the library to use an HTTP proxy, libcurl will transparently convert
operations to HTTP even if you specify an FTP URL etc. This may have an impact on
what other features of the library you can use, such as CURLOPT_QUOTE and similar
FTP specifics that don't work unless you tunnel through the HTTP proxy. Such tun-
neling is activated with CURLOPT_HTTPPROXYTUNNEL.

libcurl respects the environment variables http_proxy, ftp_proxy, all_proxy etc, if
any of those is set. The CURLOPT_PROXY option does however override any possibly
set environment variables.

Setting the proxy string to "" (an empty string) will explicitly disable the use of
a proxy, even if there is an environment variable set for it.

Since 7.14.1, the proxy host string given in environment variables can be specified
the exact same way as the proxy can be set with CURLOPT_PROXY, include protocol
prefix (http://) and embedded user + password.

CURLOPT_PROXYPORT
Pass a long with this option to set the proxy port to connect to unless it is spec-
ified in the proxy string CURLOPT_PROXY.

CURLOPT_PROXYTYPE
Pass a long with this option to set type of the proxy. Available options for this
are CURLPROXY_HTTP, CURLPROXY_SOCKS4 (added in 7.15.2), CURLPROXY_SOCKS5, CURL-
PROXY_SOCKS4A (added in 7.18.0) and CURLPROXY_SOCKS5_HOSTNAME (added in 7.18.0).
The HTTP type is default. (Added in 7.10)

CURLOPT_HTTPPROXYTUNNEL
Set the parameter to non-zero to get the library to tunnel all operations through a
given HTTP proxy. There is a big difference between using a proxy and to tunnel
through it. If you don't know what this means, you probably don't want this tunnel-
ing option.

CURLOPT_SOCKS5_RESOLVE_LOCAL
Set the parameter to 1 to get the library to resolve the host name locally instead
of passing it to the proxy to resolve, when using a SOCKS5 proxy.

Note that libcurl before 7.18.0 always resolved the host name locally even when
SOCKS5 was used. (Added in 7.18.0)

CURLOPT_INTERFACE
Pass a char * as parameter. This set the interface name to use as outgoing network
interface. The name can be an interface name, an IP address or a host name.

CURLOPT_LOCALPORT
Pass a long. This sets the local port number of the socket used for connection.
This can be used in combination with CURLOPT_INTERFACE and you are recommended to
use CURLOPT_LOCALPORTRANGE as well when this is set. Note that port numbers are
only valid 1 - 65535. (Added in 7.15.2)

CURLOPT_LOCALPORTRANGE
Pass a long. This is the number of attempts libcurl should do to find a working
local port number. It starts with the given CURLOPT_LOCALPORT and adds one to the
number for each retry. Setting this value to 1 or below will make libcurl do only
one try for exact port number. Note that port numbers by nature is a scarce
resource that will be busy at times so setting this value to something too low
might cause unnecessary connection setup failures. (Added in 7.15.2)

CURLOPT_DNS_CACHE_TIMEOUT
Pass a long, this sets the timeout in seconds. Name resolves will be kept in memory
for this number of seconds. Set to zero (0) to completely disable caching, or set
to -1 to make the cached entries remain forever. By default, libcurl caches this
info for 60 seconds.

CURLOPT_DNS_USE_GLOBAL_CACHE
Pass a long. If the value is non-zero, it tells curl to use a global DNS cache that
will survive between easy handle creations and deletions. This is not thread-safe
and this will use a global variable.

WARNING: this option is considered obsolete. Stop using it. Switch over to using
the share interface instead! See CURLOPT_SHARE and curl_share_init(3).

CURLOPT_BUFFERSIZE
Pass a long specifying your preferred size (in bytes) for the receive buffer in
libcurl. The main point of this would be that the write callback gets called more
often and with smaller chunks. This is just treated as a request, not an order. You
cannot be guaranteed to actually get the given size. (Added in 7.10)

This size is by default set as big as possible (CURL_MAX_WRITE_SIZE), so it only
makes sense to use this option if you want it smaller.

CURLOPT_PORT
Pass a long specifying what remote port number to connect to, instead of the one
specified in the URL or the default port for the used protocol.

CURLOPT_TCP_NODELAY
Pass a long specifying whether the TCP_NODELAY option should be set or cleared (1 =
set, 0 = clear). The option is cleared by default. This will have no effect after
the connection has been established.

Setting this option will disable TCP's Nagle algorithm. The purpose of this algo-
rithm is to try to minimize the number of small packets on the network (where
"small packets" means TCP segments less than the Maximum Segment Size (MSS) for the
network).

Maximizing the amount of data sent per TCP segment is good because it amortizes the
overhead of the send. However, in some cases (most notably telnet or rlogin) small
segments may need to be sent without delay. This is less efficient than sending
larger amounts of data at a time, and can contribute to congestion on the network
if overdone.

NAMES and PASSWORDS OPTIONS (Authentication)
CURLOPT_NETRC
This parameter controls the preference of libcurl between using user names and
passwords from your ~/.netrc file, relative to user names and passwords in the URL
supplied with CURLOPT_URL.

libcurl uses a user name (and supplied or prompted password) supplied with CUR-
LOPT_USERPWD in preference to any of the options controlled by this parameter.

Pass a long, set to one of the values described below.

CURL_NETRC_OPTIONAL
The use of your ~/.netrc file is optional, and information in the URL is to
be preferred. The file will be scanned with the host and user name (to find
the password only) or with the host only, to find the first user name and
password after that machine, which ever information is not specified in the
URL.

Undefined values of the option will have this effect.

CURL_NETRC_IGNORED
The library will ignore the file and use only the information in the URL.

This is the default.

CURL_NETRC_REQUIRED
This value tells the library that use of the file is required, to ignore the
information in the URL, and to search the file with the host only.
Only machine name, user name and password are taken into account (init macros and similar
things aren't supported).

libcurl does not verify that the file has the correct properties set (as the standard Unix
ftp client does). It should only be readable by user.

CURLOPT_NETRC_FILE
Pass a char * as parameter, pointing to a zero terminated string containing the
full path name to the file you want libcurl to use as .netrc file. If this option
is omitted, and CURLOPT_NETRC is set, libcurl will attempt to find the a .netrc
file in the current user's home directory. (Added in 7.10.9)

CURLOPT_USERPWD
Pass a char * as parameter, which should be [user name]:[password] to use for the
connection. Use CURLOPT_HTTPAUTH to decide authentication method.

When using NTLM, you can set domain by prepending it to the user name and separat-
ing the domain and name with a forward (/) or backward slash (\). Like this:
"domain/user:password" or "domain\user:password". Some HTTP servers (on Windows)
support this style even for Basic authentication.

When using HTTP and CURLOPT_FOLLOWLOCATION, libcurl might perform several requests
to possibly different hosts. libcurl will only send this user and password informa-
tion to hosts using the initial host name (unless CURLOPT_UNRESTRICTED_AUTH is
set), so if libcurl follows locations to other hosts it will not send the user and
password to those. This is enforced to prevent accidental information leakage.

CURLOPT_PROXYUSERPWD
Pass a char * as parameter, which should be [user name]:[password] to use for the
connection to the HTTP proxy. Use CURLOPT_PROXYAUTH to decide authentication
method.

CURLOPT_HTTPAUTH
Pass a long as parameter, which is set to a bitmask, to tell libcurl what authenti-
cation method(s) you want it to use. The available bits are listed below. If more
than one bit is set, libcurl will first query the site to see what authentication
methods it supports and then pick the best one you allow it to use. For some meth-
ods, this will induce an extra network round-trip. Set the actual name and password
with the CURLOPT_USERPWD option. (Added in 7.10.6)

CURLAUTH_BASIC
HTTP Basic authentication. This is the default choice, and the only method
that is in wide-spread use and supported virtually everywhere. This is send-
ing the user name and password over the network in plain text, easily cap-
tured by others.

CURLAUTH_DIGEST
HTTP Digest authentication. Digest authentication is defined in RFC2617 and
is a more secure way to do authentication over public networks than the reg-
ular old-fashioned Basic method.

CURLAUTH_GSSNEGOTIATE
HTTP GSS-Negotiate authentication. The GSS-Negotiate (also known as plain
"Negotiate") method was designed by Microsoft and is used in their web
applications. It is primarily meant as a support for Kerberos5 authentica-
tion but may be also used along with another authentication methods. For
more information see IETF draft draft-brezak-spnego-http-04.txt.

You need to build libcurl with a suitable GSS-API library for this to work.

CURLAUTH_NTLM
HTTP NTLM authentication. A proprietary protocol invented and used by
Microsoft. It uses a challenge-response and hash concept similar to Digest,
to prevent the password from being eavesdropped.

You need to build libcurl with OpenSSL support for this option to work, or
build libcurl on Windows.

CURLAUTH_ANY
This is a convenience macro that sets all bits and thus makes libcurl pick
any it finds suitable. libcurl will automatically select the one it finds
most secure.

CURLAUTH_ANYSAFE
This is a convenience macro that sets all bits except Basic and thus makes
libcurl pick any it finds suitable. libcurl will automatically select the
one it finds most secure.

CURLOPT_PROXYAUTH
Pass a long as parameter, which is set to a bitmask, to tell libcurl what authenti-
cation method(s) you want it to use for your proxy authentication. If more than
one bit is set, libcurl will first query the site to see what authentication meth-
ods it supports and then pick the best one you allow it to use. For some methods,
this will induce an extra network round-trip. Set the actual name and password with
the CURLOPT_PROXYUSERPWD option. The bitmask can be constructed by or'ing together
the bits listed above for the CURLOPT_HTTPAUTH option. As of this writing, only
Basic, Digest and NTLM work. (Added in 7.10.7)

HTTP OPTIONS
CURLOPT_AUTOREFERER
Pass a non-zero parameter to enable this. When enabled, libcurl will automatically
set the Referer: field in requests where it follows a Location: redirect.

CURLOPT_ENCODING
Sets the contents of the Accept-Encoding: header sent in an HTTP request, and
enables decoding of a response when a Content-Encoding: header is received. Three
encodings are supported: identity, which does nothing, deflate which requests the
server to compress its response using the zlib algorithm, and gzip which requests
the gzip algorithm. If a zero-length string is set, then an Accept-Encoding:
header containing all supported encodings is sent.

This is a request, not an order; the server may or may not do it. This option must
be set (to any non-NULL value) or else any unsolicited encoding done by the server
is ignored. See the special file lib/README.encoding for details.

CURLOPT_FOLLOWLOCATION
A non-zero parameter tells the library to follow any Location: header that the
server sends as part of an HTTP header.

This means that the library will re-send the same request on the new location and
follow new Location: headers all the way until no more such headers are returned.
CURLOPT_MAXREDIRS can be used to limit the number of redirects libcurl will follow.

NOTE: since 7.19.4, libcurl can limit to what protocols it will automatically fol-
low. The accepted protocols are set with CURLOPT_REDIR_PROTOCOLS and it excludes
the FILE protocol by default.

CURLOPT_UNRESTRICTED_AUTH
A non-zero parameter tells the library it can continue to send authentication
(user+password) when following locations, even when hostname changed. This option
is meaningful only when setting CURLOPT_FOLLOWLOCATION.

CURLOPT_MAXREDIRS
Pass a long. The set number will be the redirection limit. If that many redirec-
tions have been followed, the next redirect will cause an error
(CURLE_TOO_MANY_REDIRECTS). This option only makes sense if the CURLOPT_FOLLOWLOCA-
TION is used at the same time. Added in 7.15.1: Setting the limit to 0 will make
libcurl refuse any redirect. Set it to -1 for an infinite number of redirects
(which is the default)

CURLOPT_POST301
A non-zero parameter tells the library to respect RFC 2616/10.3.2 and not convert
POST requests into GET requests when following a 301 redirection. The non-RFC
behaviour is ubiquitous in web browsers, so the library does the conversion by
default to maintain consistency. However, a server may requires a POST to remain a
POST after such a redirection. This option is meaningful only when setting CUR-
LOPT_FOLLOWLOCATION. (Added in 7.17.1)

CURLOPT_PUT
A non-zero parameter tells the library to use HTTP PUT to transfer data. The data
should be set with CURLOPT_READDATA and CURLOPT_INFILESIZE.

This option is deprecated and starting with version 7.12.1 you should instead use
CURLOPT_UPLOAD.

CURLOPT_POST
A non-zero parameter tells the library to do a regular HTTP post. This will also
make the library use the a "Content-Type: application/x-www-form-urlencoded"
header. (This is by far the most commonly used POST method).

Use one of CURLOPT_POSTFIELDS or CURLOPT_COPYPOSTFIELDS options to specify what
data to post and CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE to set the
data size.

Optionally, you can provide data to POST using the CURLOPT_READFUNCTION and CUR-
LOPT_READDATA options but then you must make sure to not set CURLOPT_POSTFIELDS to
anything but NULL. When providing data with a callback, you must transmit it using
chunked transfer-encoding or you must set the size of the data with the CUR-
LOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE option. To enable chunked encod-
ing, you simply pass in the appropriate Transfer-Encoding header, see the post-
callback.c example.

You can override the default POST Content-Type: header by setting your own with
CURLOPT_HTTPHEADER.

Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You
can disable this header with CURLOPT_HTTPHEADER as usual.

If you use POST to a HTTP 1.1 server, you can send data without knowing the size
before starting the POST if you use chunked encoding. You enable this by adding a
header like "Transfer-Encoding: chunked" with CURLOPT_HTTPHEADER. With HTTP 1.0 or
without chunked transfer, you must specify the size in the request.

When setting CURLOPT_POST to a non-zero value, it will automatically set CUR-
LOPT_NOBODY to 0 (since 7.14.1).

If you issue a POST request and then want to make a HEAD or GET using the same re-
used handle, you must explicitly set the new request type using CURLOPT_NOBODY or
CURLOPT_HTTPGET or similar.

CURLOPT_POSTFIELDS
Pass a void * as parameter, which should be the full data to post in an HTTP POST
operation. You must make sure that the data is formatted the way you want the
server to receive it. libcurl will not convert or encode it for you. Most web
servers will assume this data to be url-encoded. Take note.

The pointed data are NOT copied by the library: as a consequence, they must be pre-
served by the calling application until the transfer finishes.

This POST is a normal application/x-www-form-urlencoded kind (and libcurl will set
that Content-Type by default when this option is used), which is the most commonly
used one by HTML forms. See also the CURLOPT_POST. Using CURLOPT_POSTFIELDS implies
CURLOPT_POST.

If you want to do a zero-byte POST, you need to set CURLOPT_POSTFIELDSIZE explic-
itly to zero, as simply setting CURLOPT_POSTFIELDS to NULL or "" just effectively
disables the sending of the specified string. libcurl will instead assume that
you'll send the POST data using the read callback!

Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You
can disable this header with CURLOPT_HTTPHEADER as usual.

To make multipart/formdata posts (aka rfc1867-posts), check out the CURLOPT_HTTP-
POST option.

CURLOPT_POSTFIELDSIZE
If you want to post data to the server without letting libcurl do a strlen() to
measure the data size, this option must be used. When this option is used you can
post fully binary data, which otherwise is likely to fail. If this size is set to
-1, the library will use strlen() to get the size.

CURLOPT_POSTFIELDSIZE_LARGE
Pass a curl_off_t as parameter. Use this to set the size of the CURLOPT_POSTFIELDS
data to prevent libcurl from doing strlen() on the data to figure out the size.
This is the large file version of the CURLOPT_POSTFIELDSIZE option. (Added in
7.11.1)

CURLOPT_COPYPOSTFIELDS
Pass a char * as parameter, which should be the full data to post in an HTTP POST
operation. It behaves as the CURLOPT_POSTFIELDS option, but the original data are
copied by the library, allowing the application to overwrite the original data
after setting this option.

Because data are copied, care must be taken when using this option in conjunction
with CURLOPT_POSTFIELDSIZE or CURLOPT_POSTFIELDSIZE_LARGE: If the size has not been
set prior to CURLOPT_COPYPOSTFIELDS, the data are assumed to be a NUL-terminated
string; else the stored size informs the library about the data byte count to copy.
In any case, the size must not be changed after CURLOPT_COPYPOSTFIELDS, unless
another CURLOPT_POSTFIELDS or CURLOPT_COPYPOSTFIELDS option is issued. (Added in
7.17.1)

CURLOPT_HTTPPOST
Tells libcurl you want a multipart/formdata HTTP POST to be made and you instruct
what data to pass on to the server. Pass a pointer to a linked list of curl_http-
post structs as parameter. . The easiest way to create such a list, is to use
curl_formadd(3) as documented. The data in this list must remain intact until you
close this curl handle again with curl_easy_cleanup(3).

Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You
can disable this header with CURLOPT_HTTPHEADER as usual.

When setting CURLOPT_HTTPPOST, it will automatically set CURLOPT_NOBODY to 0 (since
7.14.1).

CURLOPT_REFERER
Pass a pointer to a zero terminated string as parameter. It will be used to set the
Referer: header in the http request sent to the remote server. This can be used to
fool servers or scripts. You can also set any custom header with CURLOPT_HTTP-
HEADER.

CURLOPT_USERAGENT
Pass a pointer to a zero terminated string as parameter. It will be used to set the
User-Agent: header in the http request sent to the remote server. This can be used
to fool servers or scripts. You can also set any custom header with CURLOPT_HTTP-
HEADER.

CURLOPT_HTTPHEADER
Pass a pointer to a linked list of HTTP headers to pass to the server in your HTTP
request. The linked list should be a fully valid list of struct curl_slist structs
properly filled in. Use curl_slist_append(3) to create the list and
curl_slist_free_all(3) to clean up an entire list. If you add a header that is oth-
erwise generated and used by libcurl internally, your added one will be used
instead. If you add a header with no contents as in 'Accept:' (no data on the right
side of the colon), the internally used header will get disabled. Thus, using this
option you can add new headers, replace internal headers and remove internal head-
ers. To add a header with no contents, make the contents be two quotes: "". The
headers included in the linked list must not be CRLF-terminated, because curl adds
CRLF after each header item. Failure to comply with this will result in strange
bugs because the server will most likely ignore part of the headers you specified.

The first line in a request (containing the method, usually a GET or POST) is not a
header and cannot be replaced using this option. Only the lines following the
request-line are headers. Adding this method line in this list of headers will only
cause your request to send an invalid header.

Pass a NULL to this to reset back to no custom headers.

The most commonly replaced headers have "shortcuts" in the options CURLOPT_COOKIE,
CURLOPT_USERAGENT and CURLOPT_REFERER.

CURLOPT_HTTP200ALIASES
Pass a pointer to a linked list of aliases to be treated as valid HTTP 200
responses. Some servers respond with a custom header response line. For example,
IceCast servers respond with "ICY 200 OK". By including this string in your list
of aliases, the response will be treated as a valid HTTP header line such as
"HTTP/1.0 200 OK". (Added in 7.10.3)

The linked list should be a fully valid list of struct curl_slist structs, and be
properly filled in. Use curl_slist_append(3) to create the list and
curl_slist_free_all(3) to clean up an entire list.

The alias itself is not parsed for any version strings. Before libcurl 7.16.3,
Libcurl used the value set by option CURLOPT_HTTP_VERSION, but starting with 7.16.3
the protocol is assumed to match HTTP 1.0 when an alias matched.

CURLOPT_COOKIE
Pass a pointer to a zero terminated string as parameter. It will be used to set a
cookie in the http request. The format of the string should be NAME=CONTENTS, where
NAME is the cookie name and CONTENTS is what the cookie should contain.

If you need to set multiple cookies, you need to set them all using a single option
and thus you need to concatenate them all in one single string. Set multiple cook-
ies in one string like this: "name1=content1; name2=content2;" etc.

Note that this option sets the cookie header explictly in the outgoing request(s).
If multiple requests are done due to authentication, followed redirections or simi-
lar, they will all get this cookie passed on.

Using this option multiple times will only make the latest string override the pre-
vious ones.

CURLOPT_COOKIEFILE
Pass a pointer to a zero terminated string as parameter. It should contain the name
of your file holding cookie data to read. The cookie data may be in Netscape /
Mozilla cookie data format or just regular HTTP-style headers dumped to a file.

Given an empty or non-existing file or by passing the empty string (""), this
option will enable cookies for this curl handle, making it understand and parse
received cookies and then use matching cookies in future request.

If you use this option multiple times, you just add more files to read. Subsequent
files will add more cookies.

CURLOPT_COOKIEJAR
Pass a file name as char *, zero terminated. This will make libcurl write all
internally known cookies to the specified file when curl_easy_cleanup(3) is called.
If no cookies are known, no file will be created. Specify "-" to instead have the
cookies written to stdout. Using this option also enables cookies for this session,
so if you for example follow a location it will make matching cookies get sent
accordingly.

If the cookie jar file can't be created or written to (when the
curl_easy_cleanup(3) is called), libcurl will not and cannot report an error for
this. Using CURLOPT_VERBOSE or CURLOPT_DEBUGFUNCTION will get a warning to display,
but that is the only visible feedback you get about this possibly lethal situation.

CURLOPT_COOKIESESSION
Pass a long set to non-zero to mark this as a new cookie "session". It will force
libcurl to ignore all cookies it is about to load that are "session cookies" from
the previous session. By default, libcurl always stores and loads all cookies,
independent if they are session cookies are not. Session cookies are cookies with-
out expiry date and they are meant to be alive and existing for this "session"
only.

CURLOPT_COOKIELIST
Pass a char * to a cookie string. Cookie can be either in Netscape / Mozilla format
or just regular HTTP-style header (Set-Cookie: ...) format. If cURL cookie engine
was not enabled it will enable its cookie engine. Passing a magic string "ALL"
will erase all cookies known by cURL. (Added in 7.14.1) Passing the special string
"SESS" will only erase all session cookies known by cURL. (Added in 7.15.4) Passing
the special string "FLUSH" will write all cookies known by cURL to the file speci-
fied by CURLOPT_COOKIEJAR. (Added in 7.17.1)

CURLOPT_HTTPGET
Pass a long. If the long is non-zero, this forces the HTTP request to get back to
GET. usable if a POST, HEAD, PUT or a custom request have been used previously
using the same curl handle.

When setting CURLOPT_HTTPGET to a non-zero value, it will automatically set
CURLOPT_NOBODY to 0 (since 7.14.1).

CURLOPT_HTTP_VERSION
Pass a long, set to one of the values described below. They force libcurl to use
the specific HTTP versions. This is not sensible to do unless you have a good rea-
son.

CURL_HTTP_VERSION_NONE
We don't care about what version the library uses. libcurl will use whatever
it thinks fit.

CURL_HTTP_VERSION_1_0
Enforce HTTP 1.0 requests.

CURL_HTTP_VERSION_1_1
Enforce HTTP 1.1 requests.

CURLOPT_IGNORE_CONTENT_LENGTH
Ignore the Content-Length header. This is useful for Apache 1.x (and similar
servers) which will report incorrect content length for files over 2 gigabytes. If
this option is used, curl will not be able to accurately report progress, and will
simply stop the download when the server ends the connection. (added in 7.14.1)

CURLOPT_HTTP_CONTENT_DECODING
Pass a long to tell libcurl how to act on content decoding. If set to zero, content
decoding will be disabled. If set to 1 it is enabled. Note however that libcurl has
no default content decoding but requires you to use CURLOPT_ENCODING for that.
(added in 7.16.2)

CURLOPT_HTTP_TRANSFER_DECODING
Pass a long to tell libcurl how to act on transfer decoding. If set to zero, trans-
fer decoding will be disabled, if set to 1 it is enabled (default). libcurl does
chunked transfer decoding by default unless this option is set to zero. (added in
7.16.2)

FTP OPTIONS
CURLOPT_FTPPORT
Pass a pointer to a zero terminated string as parameter. It will be used to get the
IP address to use for the ftp PORT instruction. The PORT instruction tells the
remote server to connect to our specified IP address. The string may be a plain IP
address, a host name, an network interface name (under Unix) or just a '-' letter
to let the library use your systems default IP address. Default FTP operations are
passive, and thus won't use PORT.

You disable PORT again and go back to using the passive version by setting this
option to NULL.

CURLOPT_QUOTE
Pass a pointer to a linked list of FTP or SFTP commands to pass to the server prior
to your ftp request. This will be done before any other commands are issued (even
before the CWD command for FTP). The linked list should be a fully valid list of
'struct curl_slist' structs properly filled in with text strings. Use
curl_slist_append(3) to append strings (commands) to the list, and clear the entire
list afterwards with curl_slist_free_all(3). Disable this operation again by set-
ting a NULL to this option. The valid SFTP commands are: chgrp, chmod, chown, ln,
mkdir, pwd, rename, rm, rmdir, symlink. (SFTP support added in 7.16.3)

CURLOPT_POSTQUOTE
Pass a pointer to a linked list of FTP or SFTP commands to pass to the server after
your ftp transfer request. The linked list should be a fully valid list of struct
curl_slist structs properly filled in as described for CURLOPT_QUOTE. Disable this
operation again by setting a NULL to this option.

CURLOPT_PREQUOTE
Pass a pointer to a linked list of FTP commands to pass to the server after the
transfer type is set. The linked list should be a fully valid list of struct
curl_slist structs properly filled in as described for CURLOPT_QUOTE. Disable this
operation again by setting a NULL to this option. Before version 7.15.6, if you
also set CURLOPT_NOBODY non-zero, this option didn't work.

CURLOPT_DIRLISTONLY
A non-zero parameter tells the library to just list the names of files in a direc-
tory, instead of doing a full directory listing that would include file sizes,
dates etc. This works for FTP and SFTP URLs.

This causes an FTP NLST command to be sent on an FTP server. Beware that some FTP
servers list only files in their response to NLST; they might not include subdirec-
tories and symbolic links.

(This option was known as CURLOPT_FTPLISTONLY up to 7.16.4)

CURLOPT_APPEND
A non-zero parameter tells the library to append to the remote file instead of
overwrite it. This is only useful when uploading to an ftp site.

(This option was known as CURLOPT_FTPAPPEND up to 7.16.4)

CURLOPT_FTP_USE_EPRT
Pass a long. If the value is non-zero, it tells curl to use the EPRT (and LPRT)
command when doing active FTP downloads (which is enabled by CURLOPT_FTPPORT).
Using EPRT means that it will first attempt to use EPRT and then LPRT before using
PORT, but if you pass FALSE (zero) to this option, it will not try using EPRT or
LPRT, only plain PORT. (Added in 7.10.5)

If the server is an IPv6 host, this option will have no effect as of 7.12.3.

CURLOPT_FTP_USE_EPSV
Pass a long. If the value is non-zero, it tells curl to use the EPSV command when
doing passive FTP downloads (which it always does by default). Using EPSV means
that it will first attempt to use EPSV before using PASV, but if you pass FALSE
(zero) to this option, it will not try using EPSV, only plain PASV.

If the server is an IPv6 host, this option will have no effect as of 7.12.3.

CURLOPT_FTP_CREATE_MISSING_DIRS
Pass a long. If the value is non-zero, curl will attempt to create any remote
directory that it fails to CWD into. CWD is the command that changes working direc-
tory. (Added in 7.10.7)

This setting also applies to SFTP-connections. curl will attempt to create the
remote directory if it can't obtain a handle to the target-location. The creation
will fail if a file of the same name as the directory to create already exists or
lack of permissions prevents creation. (Added in 7.16.3)

CURLOPT_FTP_RESPONSE_TIMEOUT
Pass a long. Causes curl to set a timeout period (in seconds) on the amount of
time that the server is allowed to take in order to generate a response message for
a command before the session is considered hung. While curl is waiting for a
response, this value overrides CURLOPT_TIMEOUT. It is recommended that if used in
conjunction with CURLOPT_TIMEOUT, you set CURLOPT_FTP_RESPONSE_TIMEOUT to a value
smaller than CURLOPT_TIMEOUT. (Added in 7.10.8)

CURLOPT_FTP_ALTERNATIVE_TO_USER
Pass a char * as parameter, pointing to a string which will be used to authenticate
if the usual FTP "USER user" and "PASS password" negotiation fails. This is cur-
rently only known to be required when connecting to Tumbleweed's Secure Transport
FTPS server using client certificates for authentication. (Added in 7.15.5)

CURLOPT_FTP_SKIP_PASV_IP
Pass a long. If set to a non-zero value, it instructs libcurl to not use the IP
address the server suggests in its 227-response to libcurl's PASV command when
libcurl connects the data connection. Instead libcurl will re-use the same IP
address it already uses for the control connection. But it will use the port number
from the 227-response. (Added in 7.14.2)

This option has no effect if PORT, EPRT or EPSV is used instead of PASV.

CURLOPT_USE_SSL
Pass a long using one of the values from below, to make libcurl use your desired
level of SSL for the ftp transfer. (Added in 7.11.0)

(This option was known as CURLOPT_FTP_SSL up to 7.16.4, and the constants were
known as CURLFTPSSL_*)

CURLUSESSL_NONE
Don't attempt to use SSL.

CURLUSESSL_TRY
Try using SSL, proceed as normal otherwise.

CURLUSESSL_CONTROL
Require SSL for the control connection or fail with CURLE_USE_SSL_FAILED.

CURLUSESSL_ALL
Require SSL for all communication or fail with CURLE_USE_SSL_FAILED.

CURLOPT_FTPSSLAUTH
Pass a long using one of the values from below, to alter how libcurl issues "AUTH
TLS" or "AUTH SSL" when FTP over SSL is activated (see CURLOPT_FTP_SSL). (Added in
7.12.2)

CURLFTPAUTH_DEFAULT
Allow libcurl to decide

CURLFTPAUTH_SSL
Try "AUTH SSL" first, and only if that fails try "AUTH TLS"

CURLFTPAUTH_TLS
Try "AUTH TLS" first, and only if that fails try "AUTH SSL"

CURLOPT_FTP_SSL_CCC
If enabled, this option makes libcurl use CCC (Clear Command Channel). It shuts
down the SSL/TLS layer after authenticating. The rest of the control channel commu-
nication will be unencrypted. This allows NAT routers to follow the FTP transac-
tion. Pass a long using one of the values below. (Added in 7.16.1)

CURLFTPSSL_CCC_NONE
Don't attempt to use CCC.

CURLFTPSSL_CCC_PASSIVE
Do not initiate the shutdown, but wait for the server to do it. Do not send
a reply.

CURLFTPSSL_CCC_ACTIVE
Initiate the shutdown and wait for a reply.

CURLOPT_FTP_ACCOUNT
Pass a pointer to a zero-terminated string (or NULL to disable). When an FTP server
asks for "account data" after user name and password has been provided, this data
is sent off using the ACCT command. (Added in 7.13.0)

CURLOPT_FTP_FILEMETHOD
Pass a long that should have one of the following values. This option controls what
method libcurl should use to reach a file on a FTP(S) server. The argument should
be one of the following alternatives:

CURLFTPMETHOD_MULTICWD
libcurl does a single CWD operation for each path part in the given URL. For
deep hierarchies this means very many commands. This is how RFC1738 says it
should be done. This is the default but the slowest behavior.

CURLFTPMETHOD_NOCWD
libcurl does no CWD at all. libcurl will do SIZE, RETR, STOR etc and give a
full path to the server for all these commands. This is the fastest behav-
ior.

CURLFTPMETHOD_SINGLECWD
libcurl does one CWD with the full target directory and then operates on the
file "normally" (like in the multicwd case). This is somewhat more standards
compliant than 'nocwd' but without the full penalty of 'multicwd'.

PROTOCOL OPTIONS
CURLOPT_TRANSFERTEXT
A non-zero parameter tells the library to use ASCII mode for ftp transfers, instead
of the default binary transfer. For win32 systems it does not set the stdout to
binary mode. This option can be usable when transferring text data between systems
with different views on certain characters, such as newlines or similar.

libcurl does not do a complete ASCII conversion when doing ASCII transfers over
FTP. This is a known limitation/flaw that nobody has rectified. libcurl simply sets
the mode to ascii and performs a standard transfer.

CURLOPT_PROXY_TRANSFER_MODE
Pass a long. If the value is set to 1 (one), it tells libcurl to set the transfer
mode (binary or ASCII) for FTP transfers done via an HTTP proxy, by appending
;type=a or ;type=i to the URL. Without this setting, or it being set to 0 (zero,
the default), CURLOPT_TRANSFERTEXT has no effect when doing FTP via a proxy. Beware
that not all proxies support this feature. (Added in 7.18.0)

CURLOPT_CRLF
Convert Unix newlines to CRLF newlines on transfers.

CURLOPT_RANGE
Pass a char * as parameter, which should contain the specified range you want. It
should be in the format "X-Y", where X or Y may be left out. HTTP transfers also
support several intervals, separated with commas as in "X-Y,N-M". Using this kind
of multiple intervals will cause the HTTP server to send the response document in
pieces (using standard MIME separation techniques). Pass a NULL to this option to
disable the use of ranges.

Ranges work on HTTP, FTP and FILE (since 7.18.0) transfers only.

CURLOPT_RESUME_FROM
Pass a long as parameter. It contains the offset in number of bytes that you want
the transfer to start from. Set this option to 0 to make the transfer start from
the beginning (effectively disabling resume). For FTP, set this option to -1 to
make the transfer start from the end of the target file (useful to continue an
interrupted upload).

CURLOPT_RESUME_FROM_LARGE
Pass a curl_off_t as parameter. It contains the offset in number of bytes that you
want the transfer to start from. (Added in 7.11.0)

CURLOPT_CUSTOMREQUEST
Pass a pointer to a zero terminated string as parameter. It will be used instead of
GET or HEAD when doing an HTTP request, or instead of LIST or NLST when doing an
ftp directory listing. This is useful for doing DELETE or other more or less
obscure HTTP requests. Don't do this at will, make sure your server supports the
command first.

Note that libcurl will still act and assume the keyword it would use if you didn't
set your custom one is the one in use and it will act according to that. Thus,
changing this to a HEAD when libcurl otherwise would do a GET might cause libcurl
to act funny, and similar. To switch to a proper HEAD, use CURLOPT_NOBODY, to
switch to a proper POST, use CURLOPT_POST or CURLOPT_POSTFIELDS and so on.

Restore to the internal default by setting this to NULL.

Many people have wrongly used this option to replace the entire request with their
own, including multiple headers and POST contents. While that might work in many
cases, it will cause libcurl to send invalid requests and it could possibly confuse
the remote server badly. Use CURLOPT_POST and CURLOPT_POSTFIELDS to set POST data.
Use CURLOPT_HTTPHEADER to replace or extend the set of headers sent by libcurl. Use
CURLOPT_HTTP_VERSION to change HTTP version.

CURLOPT_FILETIME
Pass a long. If it is a non-zero value, libcurl will attempt to get the modifica-
tion date of the remote document in this operation. This requires that the remote
server sends the time or replies to a time querying command. The curl_easy_get-
info(3) function with the CURLINFO_FILETIME argument can be used after a transfer
to extract the received time (if any).

CURLOPT_NOBODY
A non-zero parameter tells the library to not include the body-part in the output.
This is only relevant for protocols that have separate header and body parts. On
HTTP(S) servers, this will make libcurl do a HEAD request.

To change request to GET, you should use CURLOPT_HTTPGET. Change request to POST
with CURLOPT_POST etc.

CURLOPT_INFILESIZE
When uploading a file to a remote site, this option should be used to tell libcurl
what the expected size of the infile is. This value should be passed as a long. See
also CURLOPT_INFILESIZE_LARGE.

For uploading using SCP, this option or CURLOPT_INFILESIZE_LARGE is mandatory.

Note that this option does not limit how much data libcurl will actually send, as
that is controlled entirely by what the read callback returns.

CURLOPT_INFILESIZE_LARGE
When uploading a file to a remote site, this option should be used to tell libcurl
what the expected size of the infile is. This value should be passed as a
curl_off_t. (Added in 7.11.0)

For uploading using SCP, this option or CURLOPT_INFILESIZE is mandatory.

Note that this option does not limit how much data libcurl will actually send, as
that is controlled entirely by what the read callback returns.

CURLOPT_UPLOAD
A non-zero parameter tells the library to prepare for an upload. The CURLOPT_READ-
DATA and CURLOPT_INFILESIZE or CURLOPT_INFILESIZE_LARGE options are also interest-
ing for uploads. If the protocol is HTTP, uploading means using the PUT request
unless you tell libcurl otherwise.

Using PUT with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You
can disable this header with CURLOPT_HTTPHEADER as usual.

If you use PUT to a HTTP 1.1 server, you can upload data without knowing the size
before starting the transfer if you use chunked encoding. You enable this by adding
a header like "Transfer-Encoding: chunked" with CURLOPT_HTTPHEADER. With HTTP 1.0
or without chunked transfer, you must specify the size.

CURLOPT_MAXFILESIZE
Pass a long as parameter. This allows you to specify the maximum size (in bytes) of
a file to download. If the file requested is larger than this value, the transfer
will not start and CURLE_FILESIZE_EXCEEDED will be returned.

The file size is not always known prior to download, and for such files this option
has no effect even if the file transfer ends up being larger than this given limit.
This concerns both FTP and HTTP transfers.

CURLOPT_MAXFILESIZE_LARGE
Pass a curl_off_t as parameter. This allows you to specify the maximum size (in
bytes) of a file to download. If the file requested is larger than this value, the
transfer will not start and CURLE_FILESIZE_EXCEEDED will be returned. (Added in
7.11.0)

CURLOPT_TIMECONDITION
Pass a long as parameter. This defines how the CURLOPT_TIMEVALUE time value is
treated. You can set this parameter to CURL_TIMECOND_IFMODSINCE or CURL_TIME-
COND_IFUNMODSINCE. This feature applies to HTTP and FTP.

The last modification time of a file is not always known and in such instances this
feature will have no effect even if the given time condition would have not been
met.

CURLOPT_TIMEVALUE
Pass a long as parameter. This should be the time in seconds since 1 jan 1970, and
the time will be used in a condition as specified with CURLOPT_TIMECONDITION.

CONNECTION OPTIONS
CURLOPT_TIMEOUT
Pass a long as parameter containing the maximum time in seconds that you allow the
libcurl transfer operation to take. Normally, name lookups can take a considerable
time and limiting operations to less than a few minutes risk aborting perfectly
normal operations. This option will cause curl to use the SIGALRM to enable time-
outing system calls.

In unix-like systems, this might cause signals to be used unless CURLOPT_NOSIGNAL
is set.

CURLOPT_TIMEOUT_MS
Like CURLOPT_TIMEOUT but takes number of milliseconds instead. If libcurl is built
to use the standard system name resolver, that part will still use full-second res-
olution for timeouts. (Added in 7.16.2)

CURLOPT_LOW_SPEED_LIMIT
Pass a long as parameter. It contains the transfer speed in bytes per second that
the transfer should be below during CURLOPT_LOW_SPEED_TIME seconds for the library
to consider it too slow and abort.

CURLOPT_LOW_SPEED_TIME
Pass a long as parameter. It contains the time in seconds that the transfer should
be below the CURLOPT_LOW_SPEED_LIMIT for the library to consider it too slow and
abort.

CURLOPT_MAX_SEND_SPEED_LARGE
Pass a curl_off_t as parameter. If an upload exceeds this speed on cumulative
average during the transfer, the transfer will pause to keep the average rate less
than or equal to the parameter value. Defaults to unlimited speed. (Added in
7.15.5)

CURLOPT_MAX_RECV_SPEED_LARGE
Pass a curl_off_t as parameter. If a download exceeds this speed on cumulative
average during the transfer, the transfer will pause to keep the average rate less
than or equal to the parameter value. Defaults to unlimited speed. (Added in
7.15.5)

CURLOPT_MAXCONNECTS
Pass a long. The set number will be the persistent connection cache size. The set
amount will be the maximum amount of simultaneously open connections that libcurl
may cache in this easy handle. Default is 5, and there isn't much point in changing
this value unless you are perfectly aware of how this work and changes libcurl's
behaviour. This concerns connection using any of the protocols that support persis-
tent connections.

When reaching the maximum limit, curl closes the oldest one in the cache to prevent
the number of open connections to increase.

If you already have performed transfers with this curl handle, setting a smaller
MAXCONNECTS than before may cause open connections to get closed unnecessarily.

Note that if you add this easy handle to a multi handle, this setting is not being
acknowledged, but you must instead use curl_multi_setopt(3) and the CURLMOPT_MAX-
CONNECTS option.

CURLOPT_CLOSEPOLICY
(Obsolete) This option does nothing.

CURLOPT_FRESH_CONNECT
Pass a long. Set to non-zero to make the next transfer use a new (fresh) connection
by force. If the connection cache is full before this connection, one of the exist-
ing connections will be closed as according to the selected or default policy. This
option should be used with caution and only if you understand what it does. Set
this to 0 to have libcurl attempt re-using an existing connection (default behav-
ior).

CURLOPT_FORBID_REUSE
Pass a long. Set to non-zero to make the next transfer explicitly close the connec-
tion when done. Normally, libcurl keep all connections alive when done with one
transfer in case there comes a succeeding one that can re-use them. This option
should be used with caution and only if you understand what it does. Set to 0 to
have libcurl keep the connection open for possibly later re-use (default behavior).

CURLOPT_CONNECTTIMEOUT
Pass a long. It should contain the maximum time in seconds that you allow the con-
nection to the server to take. This only limits the connection phase, once it has
connected, this option is of no more use. Set to zero to disable connection timeout
(it will then only timeout on the system's internal timeouts). See also the CUR-
LOPT_TIMEOUT option.

In unix-like systems, this might cause signals to be used unless CURLOPT_NOSIGNAL
is set.

CURLOPT_CONNECTTIMEOUT_MS
Like CURLOPT_CONNECTTIMEOUT but takes number of milliseconds instead. If libcurl is
built to use the standard system name resolver, that part will still use full-sec-
ond resolution for timeouts. (Added in 7.16.2)

CURLOPT_IPRESOLVE
Allows an application to select what kind of IP addresses to use when resolving
host names. This is only interesting when using host names that resolve addresses
using more than one version of IP. The allowed values are:

CURL_IPRESOLVE_WHATEVER
Default, resolves addresses to all IP versions that your system allows.

CURL_IPRESOLVE_V4
Resolve to ipv4 addresses.

CURL_IPRESOLVE_V6
Resolve to ipv6 addresses.

CURLOPT_CONNECT_ONLY
Pass a long. A non-zero parameter tells the library to perform any required proxy
authentication and connection setup, but no data transfer.

This option is useful with the CURLINFO_LASTSOCKET option to curl_easy_getinfo(3).
The library can set up the connection and then the application can obtain the most
recently used socket for special data transfers. (Added in 7.15.2)

SSL and SECURITY OPTIONS
CURLOPT_SSLCERT
Pass a pointer to a zero terminated string as parameter. The string should be the
file name of your certificate. The default format is "PEM" and can be changed with
CURLOPT_SSLCERTTYPE.

With NSS this is the nickname of the certificate you wish to authenticate with.

CURLOPT_SSLCERTTYPE
Pass a pointer to a zero terminated string as parameter. The string should be the
format of your certificate. Supported formats are "PEM" and "DER". (Added in
7.9.3)

CURLOPT_SSLKEY
Pass a pointer to a zero terminated string as parameter. The string should be the
file name of your private key. The default format is "PEM" and can be changed with
CURLOPT_SSLKEYTYPE.

CURLOPT_SSLKEYTYPE
Pass a pointer to a zero terminated string as parameter. The string should be the
format of your private key. Supported formats are "PEM", "DER" and "ENG".

The format "ENG" enables you to load the private key from a crypto engine. In this
case CURLOPT_SSLKEY is used as an identifier passed to the engine. You have to set
the crypto engine with CURLOPT_SSLENGINE. "DER" format key file currently does not
work because of a bug in OpenSSL.

CURLOPT_KEYPASSWD
Pass a pointer to a zero terminated string as parameter. It will be used as the
password required to use the CURLOPT_SSLKEY or CURLOPT_SSH_PRIVATE_KEYFILE private
key. You never needed a pass phrase to load a certificate but you need one to load
your private key.

(This option was known as CURLOPT_SSLKEYPASSWD up to 7.16.4 and
CURLOPT_SSLCERTPASSWD up to 7.9.2)

CURLOPT_SSLENGINE
Pass a pointer to a zero terminated string as parameter. It will be used as the
identifier for the crypto engine you want to use for your private key.

If the crypto device cannot be loaded, CURLE_SSL_ENGINE_NOTFOUND is returned.

CURLOPT_SSLENGINE_DEFAULT
Sets the actual crypto engine as the default for (asymmetric) crypto operations.

If the crypto device cannot be set, CURLE_SSL_ENGINE_SETFAILED is returned.

Note that even though this option doesn't need any parameter, in some configura-
tions curl_easy_setopt might be defined as a macro taking exactly three arguments.
Therefore, it's recommended to pass 1 as parameter to this option.

CURLOPT_SSLVERSION
Pass a long as parameter to control what version of SSL/TLS to attempt to use. The
available options are:

CURL_SSLVERSION_DEFAULT
The default action. This will attempt to figure out the remote SSL protocol
version, i.e. either SSLv3 or TLSv1 (but not SSLv2, which became disabled by
default with 7.18.1).

CURL_SSLVERSION_TLSv1
Force TLSv1

CURL_SSLVERSION_SSLv2
Force SSLv2

CURL_SSLVERSION_SSLv3
Force SSLv3

CURLOPT_SSL_VERIFYPEER
Pass a long as parameter.

This option determines whether curl verifies the authenticity of the peer's cer-
tificate. A nonzero value means curl verifies; zero means it doesn't. The default
is nonzero, but before 7.10, it was zero.

When negotiating an SSL connection, the server sends a certificate indicating its
identity. Curl verifies whether the certificate is authentic, i.e. that you can
trust that the server is who the certificate says it is. This trust is based on a
chain of digital signatures, rooted in certification authority (CA) certificates
you supply. As of 7.10, curl installs a default bundle of CA certificates and you
can specify alternate certificates with the CURLOPT_CAINFO option or the CUR-
LOPT_CAPATH option.

When CURLOPT_SSL_VERIFYPEER is nonzero, and the verification fails to prove that
the certificate is authentic, the connection fails. When the option is zero, the
connection succeeds regardless.

Authenticating the certificate is not by itself very useful. You typically want to
ensure that the server, as authentically identified by its certificate, is the
server you mean to be talking to. Use CURLOPT_SSL_VERIFYHOST to control that.

CURLOPT_CAINFO
Pass a char * to a zero terminated string naming a file holding one or more cer-
tificates to verify the peer with. This makes sense only when used in combination
with the CURLOPT_SSL_VERIFYPEER option. If CURLOPT_SSL_VERIFYPEER is zero, CUR-
LOPT_CAINFO need not even indicate an accessible file.

Note that option is by default set to the system path where libcurl's cacert bundle
is assumed to be stored, as established at build time.

When built against NSS this is the directory that the NSS certificate database
resides in.

CURLOPT_CAPATH
Pass a char * to a zero terminated string naming a directory holding multiple CA
certificates to verify the peer with. The certificate directory must be prepared
using the openssl c_rehash utility. This makes sense only when used in combination
with the CURLOPT_SSL_VERIFYPEER option. If CURLOPT_SSL_VERIFYPEER is zero, CUR-
LOPT_CAPATH need not even indicate an accessible path. The CURLOPT_CAPATH function
apparently does not work in Windows due to some limitation in openssl. This option
is OpenSSL-specific and does nothing if libcurl is built to use GnuTLS.

CURLOPT_RANDOM_FILE
Pass a char * to a zero terminated file name. The file will be used to read from to
seed the random engine for SSL. The more random the specified file is, the more
secure the SSL connection will become.

CURLOPT_EGDSOCKET
Pass a char * to the zero terminated path name to the Entropy Gathering Daemon
socket. It will be used to seed the random engine for SSL.

CURLOPT_SSL_VERIFYHOST
Pass a long as parameter.

This option determines whether libcurl verifies that the server cert is for the
server it is known as.

When negotiating an SSL connection, the server sends a certificate indicating its
identity.

When CURLOPT_SSL_VERIFYHOST is 2, that certificate must indicate that the server is
the server to which you meant to connect, or the connection fails.

Curl considers the server the intended one when the Common Name field or a Subject
Alternate Name field in the certificate matches the host name in the URL to which
you told Curl to connect.

When the value is 1, the certificate must contain a Common Name field, but it
doesn't matter what name it says. (This is not ordinarily a useful setting).

When the value is 0, the connection succeeds regardless of the names in the cer-
tificate.

The default, since 7.10, is 2.

The checking this option controls is of the identity that the server claims. The
server could be lying. To control lying, see CURLOPT_SSL_VERIFYPEER.

CURLOPT_SSL_CIPHER_LIST
Pass a char *, pointing to a zero terminated string holding the list of ciphers to
use for the SSL connection. The list must be syntactically correct, it consists of
one or more cipher strings separated by colons. Commas or spaces are also accept-
able separators but colons are normally used, , - and + can be used as operators.

For OpenSSL and GnuTLS valid examples of cipher lists include 'RC4-SHA',
'SHA1+DES', 'TLSv1' and 'DEFAULT'. The default list is normally set when you com-
pile OpenSSL.

You'll find more details about cipher lists on this URL:
http://www.openssl.org/docs/apps/ciphers.html

For NSS valid examples of cipher lists include 'rsa_rc4_128_md5',
'rsa_aes_128_sha', etc. With NSS you don't add/remove ciphers. If one uses this
option then all known ciphers are disabled and only those passed in are enabled.

You'll find more details about the NSS cipher lists on this URL: http://direc-
tory.fedora.redhat.com/docs/mod_nss.html#Directives

CURLOPT_SSL_SESSIONID_CACHE
Pass a long set to 0 to disable libcurl's use of SSL session-ID caching. Set this
to 1 to enable it. By default all transfers are done using the cache. Note that
while nothing ever should get hurt by attempting to reuse SSL session-IDs, there
seem to be broken SSL implementations in the wild that may require you to disable
this in order for you to succeed. (Added in 7.16.0)

CURLOPT_KRBLEVEL
Pass a char * as parameter. Set the kerberos security level for FTP; this also
enables kerberos awareness. This is a string, 'clear', 'safe', of these, 'private'
will be used. Set the string to NULL to disable kerberos support for FTP.

(This option was known as CURLOPT_KRB4LEVEL up to 7.16.3)

SSH OPTIONS
CURLOPT_SSH_AUTH_TYPES
Pass a long set to a bitmask consisting of one or more of CURLSSH_AUTH_PUBLICKEY,
CURLSSH_AUTH_PASSWORD, CURLSSH_AUTH_HOST, CURLSSH_AUTH_KEYBOARD. Set
CURLSSH_AUTH_ANY to let libcurl pick one. (Added in 7.16.1)

CURLOPT_SSH_HOST_PUBLIC_KEY_MD5
Pass a char * pointing to a string containing 32 hexadecimal digits. The string
should be the 128 bit MD5 cheksum of the remote host's public key, and libcurl will
reject the connection to the host unless the md5sums match. This option is only for
SCP and SFTP transfers. (Added in 7.17.1)

CURLOPT_SSH_PUBLIC_KEYFILE
Pass a char * pointing to a file name for your public key. If not used, libcurl
defaults to using ~/.ssh/id_dsa.pub. (Added in 7.16.1)

CURLOPT_SSH_PRIVATE_KEYFILE
Pass a char * pointing to a file name for your private key. If not used, libcurl
defaults to using ~/.ssh/id_dsa. If the file is password-protected, set the pass-
word with CURLOPT_KEYPASSWD. (Added in 7.16.1)

OTHER OPTIONS
CURLOPT_PRIVATE
Pass a void * as parameter, pointing to data that should be associated with this
curl handle. The pointer can subsequently be retrieved using curl_easy_getinfo(3)
with the CURLINFO_PRIVATE option. libcurl itself does nothing with this data.
(Added in 7.10.3)

CURLOPT_SHARE
Pass a share handle as a parameter. The share handle must have been created by a
previous call to curl_share_init(3). Setting this option, will make this curl han-
dle use the data from the shared handle instead of keeping the data to itself. This
enables several curl handles to share data. If the curl handles are used simultane-
ously, you MUST use the locking methods in the share handle. See
curl_share_setopt(3) for details.

If you add a share that is set to share cookies, your easy handle will use that
cookie cache and get the cookie engine enabled. If you unshare an object that were
using cookies (or change to another object that doesn't share cookies), the easy
handle will get its cookie engine disabled.

Data that the share object is not set to share will be dealt with the usual way, as
if no share was used.

CURLOPT_NEW_FILE_PERMS
Pass a long as a parameter, containing the value of the permissions that will be
assigned to newly created files on the remote server. The default value is 0644,
but any valid value can be used. The only protocols that can use this are sftp://,
scp:// and file://. (Added in 7.16.4)

CURLOPT_NEW_DIRECTORY_PERMS
Pass a long as a parameter, containing the value of the permissions that will be
assigned to newly created directories on the remote server. The default value is
0755, but any valid value can be used. The only protocols that can use this are
sftp://, scp:// and file://. (Added in 7.16.4)

TELNET OPTIONS
CURLOPT_TELNETOPTIONS
Provide a pointer to a curl_slist with variables to pass to the telnet negotia-
tions. The variables should be in the format <option=value>. libcurl supports the
options 'TTYPE', 'XDISPLOC' and 'NEW_ENV'. See the TELNET standard for details.

RETURN VALUE
CURLE_OK (zero) means that the option was set properly, non-zero means an error occurred
as <curl/curl.h> defines. See the libcurl-errors(3) man page for the full list with
descriptions.

If you try to set an option that libcurl doesn't know about, perhaps because the library
is too old to support it or the option was removed in a recent version, this function will
return CURLE_FAILED_INIT.

SEE ALSO
curl_easy_init(3), curl_easy_cleanup(3), curl_easy_reset(3),

libcurl 7.18.0 5 Jan 2008 curl_easy_setopt(3)

Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2012-05-25 15:37 @38.107.179.236 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)