~ubuntu-branches/ubuntu/lucid/curl/lucid-security

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 <a class="emphasis" href="./curl_easy_reset.html">curl_easy_reset(3)</a>.

NOTE: strings passed to libcurl as 'char *' arguments, will not be copied by the library. Instead you should keep them available until libcurl no longer needs them. Failing to do so will cause very odd behavior or even crashes. libcurl will need them until you call <a class="emphasis" href="./curl_easy_cleanup.html">curl_easy_cleanup(3)</a> or you set the same option again to use a different pointer.

Strings passed to libcurl as 'char *' arguments, will not be copied by the library. Instead you should keep them available until libcurl no longer needs them. Failing to do so will cause very odd behavior or even crashes. libcurl will need them until you call <a class="emphasis" href="./curl_easy_cleanup.html">curl_easy_cleanup(3)</a> or you set the same option again to use a different pointer.

The handle is the return code from a <a class="emphasis" href="./curl_easy_init.html">curl_easy_init(3)</a> or <a class="emphasis" href="./curl_easy_duphandle.html">curl_easy_duphandle(3)</a> call. <a name="BEHAVIOR"></a><h2 class="nroffsh">BEHAVIOR OPTIONS</h2>

<a name="CURLOPTVERBOSE"></a>CURLOPT_VERBOSE

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).

<a name="CURLOPTNOPROGRESS"></a>CURLOPT_NOPROGRESS

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

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

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

<a name="CURLOPTNOSIGNAL"></a>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. <a name="CALLBACK"></a><h2 class="nroffsh">CALLBACK OPTIONS</h2>

<a name="CURLOPTWRITEFUNCTION"></a>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 terminated. 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.

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 <a class="emphasis" href="#CURLOPTWRITEDATA">CURLOPT_WRITEDATA</a>.

Set the stream argument with the <a class="emphasis" href="#CURLOPTWRITEDATA">CURLOPT_WRITEDATA</a> option.

NOTE: you 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.

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.

<a name="CURLOPTWRITEDATA"></a>CURLOPT_WRITEDATA

Data pointer to pass to the file write function. Note that if you specify the <a class="emphasis" href="#CURLOPTWRITEFUNCTION">CURLOPT_WRITEFUNCTION</a>, 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.

NOTE: If you're using libcurl as a win32 DLL, you MUST use the <a class="emphasis" href="#CURLOPTWRITEFUNCTION">CURLOPT_WRITEFUNCTION</a> if you set this option or you will experience crashes.

Data pointer to pass to the file write function. If you use the <a class="emphasis" href="#CURLOPTWRITEFUNCTION">CURLOPT_WRITEFUNCTION</a> 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 <a class="emphasis" href="#CURLOPTWRITEFUNCTION">CURLOPT_WRITEFUNCTION</a> 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 <a class="emphasis" href="#CURLOPTWRITEFUNCTION">CURLOPT_WRITEFUNCTION</a> if you set this option or you will experience crashes.

This option is also known with the older name CURLOPT_FILE, the name <a class="emphasis" href="#CURLOPTWRITEDATA">CURLOPT_WRITEDATA</a> was introduced in 7.9.7.

<a name="CURLOPTREADFUNCTION"></a>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.

In libcurl 7.12.1 and later, the read callback may return CURL_READFUNC_ABORT to stop the current operation at once, with a CURLE_ABORTED_BY_CALLBACK error code from the transfer.

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)

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 <a class="emphasis" href="#CURLOPTREADDATA">CURLOPT_READDATA</a>.

<a name="CURLOPTREADDATA"></a>CURLOPT_READDATA

Data pointer to pass to the file read function. Note that if you specify the <a class="emphasis" href="#CURLOPTREADFUNCTION">CURLOPT_READFUNCTION</a>, this is the pointer you'll get as input. If you don't specify a read callback, this must be a valid FILE *.

NOTE: If you're using libcurl as a win32 DLL, you MUST use a <a class="emphasis" href="#CURLOPTREADFUNCTION">CURLOPT_READFUNCTION</a> if you set this option.

Data pointer to pass to the file read function. If you use the <a class="emphasis" href="#CURLOPTREADFUNCTION">CURLOPT_READFUNCTION</a> option, this is the pointer you'll get as input. If you don't specify a read callback 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 <a class="emphasis" href="#CURLOPTREADFUNCTION">CURLOPT_READFUNCTION</a> if you set this option.

This option is also known with the older name CURLOPT_INFILE, the name <a class="emphasis" href="#CURLOPTREADDATA">CURLOPT_READDATA</a> was introduced in 7.9.7.

<a name="CURLOPTIOCTLFUNCTION"></a>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. (Opion added in 7.12.3)

Pass a pointer that will be untouched by libcurl and passed as the 3rd argument in the ioctl callback set with <a class="emphasis" href="#CURLOPTIOCTLFUNCTION">CURLOPT_IOCTLFUNCTION</a>. (Option added in 7.12.3)

<a name="CURLOPTPROGRESSFUNCTION"></a>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 equivalent with a frequent interval during data transfer. Unknown/unused argument values 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.

Also note that <a class="emphasis" href="#CURLOPTNOPROGRESS">CURLOPT_NOPROGRESS</a> must be set to FALSE to make this function actually get called.

<a class="emphasis" href="#CURLOPTNOPROGRESS">CURLOPT_NOPROGRESS</a> must be set to FALSE to make this function actually get called.

<a name="CURLOPTPROGRESSDATA"></a>CURLOPT_PROGRESSDATA

Pass a pointer that will be untouched by libcurl and passed as the first argument in the progress callback set with <a class="emphasis" href="#CURLOPTPROGRESSFUNCTION">CURLOPT_PROGRESSFUNCTION</a>.

<a name="CURLOPTHEADERFUNCTION"></a>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 there is received header data that needs to be written down. The headers are guaranteed to be written one-by-one and only complete lines are written. Parsing headers should be easy enough using this. The size of the data pointed to by ptr is size multiplied with nmemb. The pointer named stream will be the one you passed to libcurl with the <a class="emphasis" href="#CURLOPTWRITEHEADER">CURLOPT_WRITEHEADER</a> option. Return the number of bytes actually written or return -1 to signal error to the library (it will cause it to abort the transfer with a CURLE_WRITE_ERROR return code).

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 <a class="emphasis" href="#CURLOPTWRITEHEADER">CURLOPT_WRITEHEADER</a> 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).

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.

<a name="CURLOPTWRITEHEADER"></a>CURLOPT_WRITEHEADER

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 <a class="emphasis" href="#CURLOPTHEADERFUNCTION">CURLOPT_HEADERFUNCTION</a> option above on how to set a custom get-all-headers callback.

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(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 <a class="emphasis" href="#CURLOPTHEADERFUNCTION">CURLOPT_HEADERFUNCTION</a> option above on how to set a custom get-all-headers callback.

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<a name="CURLOPTDEBUGFUNCTION"></a>CURLOPT_DEBUGFUNCTION

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Function pointer that should match the following prototype: int curl_debug_callback (CURL *, curl_infotype, char *, size_t, void *); <a class="emphasis" href="#CURLOPTDEBUGFUNCTION">CURLOPT_DEBUGFUNCTION</a> replaces the standard debug function used when <a class="emphasis" href="#CURLOPTVERBOSE">CURLOPT_VERBOSE </a> 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.

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Available curl_infotype values:

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Pass a pointer to whatever you want passed in to your <a class="emphasis" href="#CURLOPTDEBUGFUNCTION">CURLOPT_DEBUGFUNCTION</a> in the last void * argument. This pointer is not used by libcurl, it is only passed to the callback.

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<a name="CURLOPTSSLCTXFUNCTION"></a>CURLOPT_SSL_CTX_FUNCTION

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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 function. Set the parm argument with the <a class="emphasis" href="#CURLOPTSSLCTXDATA">CURLOPT_SSL_CTX_DATA</a> option. This option was introduced in 7.11.0.

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NOTE: 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 section for a replacement of the key, certificate and trust file settings.

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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.

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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 section for a replacement of the key, certificate and trust file settings.

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<a name="CURLOPTSSLCTXDATA"></a>CURLOPT_SSL_CTX_DATA

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Data pointer to pass to the ssl context callback set by the option <a class="emphasis" href="#CURLOPTSSLCTXFUNCTION">CURLOPT_SSL_CTX_FUNCTION</a>, this is the pointer you'll get as third parameter, otherwise NULL. (Added in 7.11.0) <a name="ERROR"></a><h2 class="nroffsh">ERROR OPTIONS</h2>

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<a name="CURLOPTERRORBUFFER"></a>CURLOPT_ERRORBUFFER

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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 the library. The buffer must be at least CURL_ERROR_SIZE big.

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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.

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Use <a class="emphasis" href="#CURLOPTVERBOSE">CURLOPT_VERBOSE</a> and <a class="emphasis" href="#CURLOPTDEBUGFUNCTION">CURLOPT_DEBUGFUNCTION</a> to better debug/trace why errors happen.

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

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

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<a name="CURLOPTSTDERR"></a>CURLOPT_STDERR

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Pass a FILE * as parameter. Tell libcurl to use this stream instead of stderr when showing the progress meter and displaying <a class="emphasis" href="#CURLOPTVERBOSE">CURLOPT_VERBOSE</a> data.

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<a name="CURLOPTFAILONERROR"></a>CURLOPT_FAILONERROR

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<a name="CURLOPTURL"></a>CURLOPT_URL

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The actual URL to deal with. The parameter should be a char * to a zero terminated string. The string must remain present until curl no longer needs it, as it doesn't copy the string.

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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 <a class="emphasis" href="./curl_easy_perform.html">curl_easy_perform(3)</a> or <a class="emphasis" href="./curl_multi_perform.html">curl_multi_perform(3)</a>. Use <a class="emphasis" href="./curl_version_info.html">curl_version_info(3)</a> for detailed info on which protocols that are supported.

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NOTE: <a class="emphasis" href="#CURLOPTURL">CURLOPT_URL</a> is the only option that must be set before <a class="emphasis" href="./curl_easy_perform.html">curl_easy_perform(3)</a> is called.

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<a class="emphasis" href="#CURLOPTURL">CURLOPT_URL</a> is the only option that must be set before <a class="emphasis" href="./curl_easy_perform.html">curl_easy_perform(3)</a> is called.

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<a name="CURLOPTPROXY"></a>CURLOPT_PROXY

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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 <a class="emphasis" href="#CURLOPTPROXYPORT">CURLOPT_PROXYPORT</a>.

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NOTE: 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 <a class="emphasis" href="#CURLOPTQUOTE">CURLOPT_QUOTE</a> and similar FTP specifics that don't work unless you tunnel through the HTTP proxy. Such tunneling is activated with <a class="emphasis" href="#CURLOPTHTTPPROXYTUNNEL">CURLOPT_HTTPPROXYTUNNEL</a>.

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NOTE2: libcurl respects the environment variables http_proxy, ftp_proxy, all_proxy etc, if any of those is set.

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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 <a class="emphasis" href="#CURLOPTQUOTE">CURLOPT_QUOTE</a> and similar FTP specifics that don't work unless you tunnel through the HTTP proxy. Such tunneling is activated with <a class="emphasis" href="#CURLOPTHTTPPROXYTUNNEL">CURLOPT_HTTPPROXYTUNNEL</a>.

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libcurl respects the environment variables http_proxy, ftp_proxy, all_proxy etc, if any of those is set. The <a class="emphasis" href="#CURLOPTPROXY">CURLOPT_PROXY</a> option does however override any possibly set environment variables.

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

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<a name="CURLOPTPROXYPORT"></a>CURLOPT_PROXYPORT

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Pass a long with this option to set the proxy port to connect to unless it is specified in the proxy string <a class="emphasis" href="#CURLOPTPROXY">CURLOPT_PROXY</a>.

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<a name="CURLOPTPROXYTYPE"></a>CURLOPT_PROXYTYPE

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Pass a long with this option to set type of the proxy. Available options for this are CURLPROXY_HTTP and CURLPROXY_SOCKS5, with the HTTP one being default. (Added in 7.10)

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<a name="CURLOPTHTTPPROXYTUNNEL"></a>CURLOPT_HTTPPROXYTUNNEL

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Set the parameter to non-zero to get the library to tunnel all operations through a given HTTP proxy. Note that 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 tunneling option.

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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 tunneling option.

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<a name="CURLOPTINTERFACE"></a>CURLOPT_INTERFACE

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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.

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<a name="CURLOPTDNSCACHETIMEOUT"></a>CURLOPT_DNS_CACHE_TIMEOUT

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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.

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WARNING: this option is considered obsolete. Stop using it. Switch over to using the share interface instead! See <a class="emphasis" href="#CURLOPTSHARE">CURLOPT_SHARE</a> and <a class="emphasis" href="./curl_share_init.html">curl_share_init(3)</a>.

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<a name="CURLOPTBUFFERSIZE"></a>CURLOPT_BUFFERSIZE

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Pass a long specifying your preferred size 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)

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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)

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

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<a name="CURLOPTPORT"></a>CURLOPT_PORT

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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.

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<a name="CURLOPTTCPNODELAY"></a>CURLOPT_TCP_NODELAY

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<a name="CURLOPTNETRC"></a>CURLOPT_NETRC

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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 <a class="emphasis" href="#CURLOPTURL">CURLOPT_URL</a>.

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Note: libcurl uses a user name (and supplied or prompted password) supplied with <a class="emphasis" href="#CURLOPTUSERPWD">CURLOPT_USERPWD</a> in preference to any of the options controlled by this parameter.

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libcurl uses a user name (and supplied or prompted password) supplied with <a class="emphasis" href="#CURLOPTUSERPWD">CURLOPT_USERPWD</a> in preference to any of the options controlled by this parameter.

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

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<a name="CURLNETRCOPTIONAL"></a>CURL_NETRC_OPTIONAL

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<a name="CURLNETRCREQUIRED"></a>CURL_NETRC_REQUIRED

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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.

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Only machine name, user name and password are taken into account (init macros and similar things aren't supported).

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Note: 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.

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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.

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<a name="CURLOPTNETRCFILE"></a>CURLOPT_NETRC_FILE

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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 <a class="emphasis" href="#CURLOPTNETRC">CURLOPT_NETRC</a> is set, libcurl will attempt to find the a .netrc file in the current user's home directory. (Added in 7.10.9)

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<a name="CURLOPTUSERPWD"></a>CURLOPT_USERPWD

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Pass a char * as parameter, which should be [user name]:[password] to use for the connection. Use <a class="emphasis" href="#CURLOPTHTTPAUTH">CURLOPT_HTTPAUTH</a> to decide authentication method.

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

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When using HTTP and <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a>, libcurl might perform several requests to possibly different hosts. libcurl will only send this user and password information to hosts using the initial host name (unless <a class="emphasis" href="#CURLOPTUNRESTRICTEDAUTH">CURLOPT_UNRESTRICTED_AUTH</a> 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.

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<a name="CURLOPTPROXYUSERPWD"></a>CURLOPT_PROXYUSERPWD

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Pass a char * as parameter, which should be [user name]:[password] to use for the connection to the HTTP proxy. Use <a class="emphasis" href="#CURLOPTPROXYAUTH">CURLOPT_PROXYAUTH</a> to decide authentication method.

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<a name="CURLOPTHTTPAUTH"></a>CURLOPT_HTTPAUTH

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Pass a long as parameter, which is set to a bitmask, to tell libcurl what authentication 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. Note that for some methods, this will induce an extra network round-trip. Set the actual name and password with the <a class="emphasis" href="#CURLOPTUSERPWD">CURLOPT_USERPWD</a> option. (Added in 7.10.6)

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Pass a long as parameter, which is set to a bitmask, to tell libcurl what authentication 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 methods, this will induce an extra network round-trip. Set the actual name and password with the <a class="emphasis" href="#CURLOPTUSERPWD">CURLOPT_USERPWD</a> option. (Added in 7.10.6)

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<a name="CURLAUTHBASIC"></a>CURLAUTH_BASIC

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

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

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<a name="CURLAUTHGSSNEGOTIATE"></a>CURLAUTH_GSSNEGOTIATE

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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 authentication but may be also used along with another authentication methods. For more information see IETF draft draft-brezak-spnego-http-04.txt.

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NOTE that you need to build libcurl with a suitable GSS-API library for this to work.

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

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<a name="CURLAUTHNTLM"></a>CURLAUTH_NTLM

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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.

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NOTE that you need to build libcurl with SSL support for this option to work.

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

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<a name="CURLAUTHANY"></a>CURLAUTH_ANY

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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.

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<a name="CURLAUTHANYSAFE"></a>CURLAUTH_ANYSAFE

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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.

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<a name="CURLOPTPROXYAUTH"></a>CURLOPT_PROXYAUTH

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Pass a long as parameter, which is set to a bitmask, to tell libcurl what authentication 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 methods it supports and then pick the best one you allow it to use. Note that for some methods, this will induce an extra network round-trip. Set the actual name and password with the <a class="emphasis" href="#CURLOPTPROXYUSERPWD">CURLOPT_PROXYUSERPWD</a> option. The bitmask can be constructed by or'ing together the bits listed above for the <a class="emphasis" href="#CURLOPTHTTPAUTH">CURLOPT_HTTPAUTH</a> option. As of this writing, only Basic, Digest and NTLM work. (Added in 7.10.7) <a name="HTTP"></a><h2 class="nroffsh">HTTP OPTIONS</h2>

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Pass a long as parameter, which is set to a bitmask, to tell libcurl what authentication 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 methods 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 <a class="emphasis" href="#CURLOPTPROXYUSERPWD">CURLOPT_PROXYUSERPWD</a> option. The bitmask can be constructed by or'ing together the bits listed above for the <a class="emphasis" href="#CURLOPTHTTPAUTH">CURLOPT_HTTPAUTH</a> option. As of this writing, only Basic, Digest and NTLM work. (Added in 7.10.7) <a name="HTTP"></a><h2 class="nroffsh">HTTP OPTIONS</h2>

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<a name="CURLOPTAUTOREFERER"></a>CURLOPT_AUTOREFERER

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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.

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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.

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<a name="CURLOPTFOLLOWLOCATION"></a>CURLOPT_FOLLOWLOCATION

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

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NOTE: 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. <a class="emphasis" href="#CURLOPTMAXREDIRS">CURLOPT_MAXREDIRS</a> can be used to limit the number of redirects libcurl will follow.

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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. <a class="emphasis" href="#CURLOPTMAXREDIRS">CURLOPT_MAXREDIRS</a> can be used to limit the number of redirects libcurl will follow.

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<a name="CURLOPTUNRESTRICTEDAUTH"></a>CURLOPT_UNRESTRICTED_AUTH

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A non-zero parameter tells the library it can continue to send authentication (user+password) when following locations, even when hostname changed. Note that this is meaningful only when setting <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a>.

220

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 <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a>.

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<a name="CURLOPTMAXREDIRS"></a>CURLOPT_MAXREDIRS

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Pass a long. The set number will be the redirection limit. If that many redirections have been followed, the next redirect will cause an error (CURLE_TOO_MANY_REDIRECTS). This option only makes sense if the <a class="emphasis" href="#CURLOPTFOLLOWLOCATION">CURLOPT_FOLLOWLOCATION</a> is used at the same time.

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<a name="CURLOPTPUT"></a>CURLOPT_PUT

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A non-zero parameter tells the library to use HTTP PUT to transfer data. The data should be set with <a class="emphasis" href="#CURLOPTREADDATA">CURLOPT_READDATA</a> and <a class="emphasis" href="#CURLOPTINFILESIZE">CURLOPT_INFILESIZE</a>.

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This option is deprecated and starting with version 7.12.1 you should instead use <a class="emphasis" href="#CURLOPTUPLOAD">CURLOPT_UPLOAD</a>.

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You can override the default POST Content-Type: header by setting your own with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>.

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Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header. You can disable this header with <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a> as usual.

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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 <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>. With HTTP 1.0 or without chunked transfer, you must specify the size in the request.

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NOTE: if you have issued a POST request and want to make a HEAD or GET instead, you must explictly pick the new request type using <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> or <a class="emphasis" href="#CURLOPTHTTPGET">CURLOPT_HTTPGET</a> or similar.

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When setting <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a> to a non-zero value, it will automatically set <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> to 0 (since 7.14.1).

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If you issue a POST request and then want to make a HEAD or GET using the same re-used handle, you must explictly set the new request type using <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> or <a class="emphasis" href="#CURLOPTHTTPGET">CURLOPT_HTTPGET</a> or similar.

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<a name="CURLOPTPOSTFIELDS"></a>CURLOPT_POSTFIELDS

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Pass a char * 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.

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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 <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a>. Using <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> implies <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a>.

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Note: to make multipart/formdata posts (aka rfc1867-posts), check out the <a class="emphasis" href="#CURLOPTHTTPPOST">CURLOPT_HTTPPOST</a> option.

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To make multipart/formdata posts (aka rfc1867-posts), check out the <a class="emphasis" href="#CURLOPTHTTPPOST">CURLOPT_HTTPPOST</a> option.

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<a name="CURLOPTPOSTFIELDSIZE"></a>CURLOPT_POSTFIELDSIZE

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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.

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<a name="CURLOPTPOSTFIELDSIZELARGE"></a>CURLOPT_POSTFIELDSIZE_LARGE

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<a name="CURLOPTHTTPPOST"></a>CURLOPT_HTTPPOST

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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_httppost structs as parameter. . The easiest way to create such a list, is to use <a class="emphasis" href="./curl_formadd.html">curl_formadd(3)</a> as documented. The data in this list must remain intact until you close this curl handle again with <a class="emphasis" href="./curl_easy_cleanup.html">curl_easy_cleanup(3)</a>.

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When setting <a class="emphasis" href="#CURLOPTHTTPPOST">CURLOPT_HTTPPOST</a>, it will automatically set <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> to 0 (since 7.14.1).

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<a name="CURLOPTREFERER"></a>CURLOPT_REFERER

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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 <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>.

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<a name="CURLOPTUSERAGENT"></a>CURLOPT_USERAGENT

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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 <a class="emphasis" href="./curl_slist_append.html">curl_slist_append(3)</a> to create the list and <a class="emphasis" href="./curl_slist_free_all.html">curl_slist_free_all(3)</a> to clean up an entire list. If you add a header that is otherwise 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 headers. 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.

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The first line in a request (usually containing a GET or POST) is not a header and cannot be replaced using this option. Only the lines following the request-line are headers.

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

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NOTE: The most commonly replaced headers have "shortcuts" in the options <a class="emphasis" href="#CURLOPTCOOKIE">CURLOPT_COOKIE</a>, <a class="emphasis" href="#CURLOPTUSERAGENT">CURLOPT_USERAGENT</a> and <a class="emphasis" href="#CURLOPTREFERER">CURLOPT_REFERER</a>.

256

The most commonly replaced headers have "shortcuts" in the options <a class="emphasis" href="#CURLOPTCOOKIE">CURLOPT_COOKIE</a>, <a class="emphasis" href="#CURLOPTUSERAGENT">CURLOPT_USERAGENT</a> and <a class="emphasis" href="#CURLOPTREFERER">CURLOPT_REFERER</a>.

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<a name="CURLOPTHTTP200ALIASES"></a>CURLOPT_HTTP200ALIASES

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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)

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The linked list should be a fully valid list of struct curl_slist structs, and be properly filled in. Use <a class="emphasis" href="./curl_slist_append.html">curl_slist_append(3)</a> to create the list and <a class="emphasis" href="./curl_slist_free_all.html">curl_slist_free_all(3)</a> to clean up an entire list.

249

NOTE: The alias itself is not parsed for any version strings. So if your alias is "MYHTTP/9.9", Libcurl will not treat the server as responding with HTTP version 9.9. Instead Libcurl will use the value set by option <a class="emphasis" href="#CURLOPTHTTPVERSION">CURLOPT_HTTP_VERSION</a>.

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The alias itself is not parsed for any version strings. So if your alias is "MYHTTP/9.9", Libcurl will not treat the server as responding with HTTP version 9.9. Instead Libcurl will use the value set by option <a class="emphasis" href="#CURLOPTHTTPVERSION">CURLOPT_HTTP_VERSION</a>.

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<a name="CURLOPTCOOKIE"></a>CURLOPT_COOKIE

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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.

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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 cookies in one string like this: "name1=content1; name2=content2;" etc.

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<a name="CURLOPTCOOKIEFILE"></a>CURLOPT_COOKIEFILE

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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.

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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.

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

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<a name="CURLOPTCOOKIEJAR"></a>CURLOPT_COOKIEJAR

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Pass a file name as char *, zero terminated. This will make libcurl write all internally known cookies to the specified file when <a class="emphasis" href="./curl_easy_cleanup.html">curl_easy_cleanup(3)</a> 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.

259

NOTE: If the cookie jar file can't be created or written to (when the <a class="emphasis" href="./curl_easy_cleanup.html">curl_easy_cleanup(3)</a> is called), libcurl will not and cannot report an error for this. Using <a class="emphasis" href="#CURLOPTVERBOSE">CURLOPT_VERBOSE</a> or <a class="emphasis" href="#CURLOPTDEBUGFUNCTION">CURLOPT_DEBUGFUNCTION</a> will get a warning to display, but that is the only visible feedback you get about this possibly lethal situation.

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

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<a name="CURLOPTCOOKIESESSION"></a>CURLOPT_COOKIESESSION

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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 without expiry date and they are meant to be alive and existing for this "session" only.

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<a name="CURLOPTCOOKIELIST"></a>CURLOPT_COOKIELIST

275

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)

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<a name="CURLOPTHTTPGET"></a>CURLOPT_HTTPGET

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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.

278

When setting <a class="emphasis" href="#CURLOPTHTTPGET">CURLOPT_HTTPGET</a> to a non-zero value, it will automatically set <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> to 0 (since 7.14.1).

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<a name="CURLOPTHTTPVERSION"></a>CURLOPT_HTTP_VERSION

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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 reason.

266

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270

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Enforce HTTP 1.0 requests.

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<a name="CURLHTTPVERSION11"></a>CURL_HTTP_VERSION_1_1

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Enforce HTTP 1.1 requests.

288

<a name="CURLOPTIGNORECONTENTLENGTH"></a>CURLOPT_IGNORE_CONTENT_LENGTH

289

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)

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<a name="FTP"></a><h2 class="nroffsh">FTP OPTIONS</h2>

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275

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<a name="CURLOPTFTPPORT"></a>CURLOPT_FTPPORT

295

312

<a name="CURLOPTFTPCREATEMISSINGDIRS"></a>CURLOPT_FTP_CREATE_MISSING_DIRS

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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 directory. (Added in 7.10.7)

297

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<a name="CURLOPTFTPRESPONSETIMEOUT"></a>CURLOPT_FTP_RESPONSE_TIMEOUT

298

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. Note that while curl is waiting for a response, this value overrides <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a>. It is recommended that if used in conjunction with <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a>, you set <a class="emphasis" href="#CURLOPTFTPRESPONSETIMEOUT">CURLOPT_FTP_RESPONSE_TIMEOUT</a> to a value smaller than <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a>. (Added in 7.10.8)

315

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 <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a>. It is recommended that if used in conjunction with <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a>, you set <a class="emphasis" href="#CURLOPTFTPRESPONSETIMEOUT">CURLOPT_FTP_RESPONSE_TIMEOUT</a> to a value smaller than <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a>. (Added in 7.10.8)

316

<a name="CURLOPTFTPSKIPPASVIP"></a>CURLOPT_FTP_SKIP_PASV_IP

317

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)

318

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

299

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<a name="CURLOPTFTPSSL"></a>CURLOPT_FTP_SSL

300

320

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)

301

321

332

352

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) <a name="PROTOCOL"></a><h2 class="nroffsh">PROTOCOL OPTIONS</h2>

333

353

334

354

<a name="CURLOPTTRANSFERTEXT"></a>CURLOPT_TRANSFERTEXT

335

A non-zero parameter tells the library to use ASCII mode for ftp transfers, instead of the default binary transfer. For LDAP transfers it gets the data in plain text instead of HTML and 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.

355

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.

356

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.

336

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<a name="CURLOPTCRLF"></a>CURLOPT_CRLF

337

358

Convert Unix newlines to CRLF newlines on transfers.

338

359

<a name="CURLOPTRANGE"></a>CURLOPT_RANGE

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365

<a name="CURLOPTCUSTOMREQUEST"></a>CURLOPT_CUSTOMREQUEST

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366

Pass a pointer to a zero terminated string as parameter. It will be user 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.

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367

Restore to the internal default by setting this to NULL.

347

NOTE: 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 <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a> and <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> to set POST data. Use <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a> to replace or extend the set of headers sent by libcurl. Use <a class="emphasis" href="#CURLOPTHTTPVERSION">CURLOPT_HTTP_VERSION</a> to change HTTP version.

368

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 <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a> and <a class="emphasis" href="#CURLOPTPOSTFIELDS">CURLOPT_POSTFIELDS</a> to set POST data. Use <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a> to replace or extend the set of headers sent by libcurl. Use <a class="emphasis" href="#CURLOPTHTTPVERSION">CURLOPT_HTTP_VERSION</a> to change HTTP version.

348

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<a name="CURLOPTFILETIME"></a>CURLOPT_FILETIME

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370

Pass a long. If it is a non-zero value, libcurl will attempt to get the modification 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 <a class="emphasis" href="./curl_easy_getinfo.html">curl_easy_getinfo(3)</a> function with the CURLINFO_FILETIME argument can be used after a transfer to extract the received time (if any).

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<a name="CURLOPTNOBODY"></a>CURLOPT_NOBODY

351

372

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.

352

To change back to GET, you should use <a class="emphasis" href="#CURLOPTHTTPGET">CURLOPT_HTTPGET</a>. To change back to POST, you should use <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a>. Setting <a class="emphasis" href="#CURLOPTNOBODY">CURLOPT_NOBODY</a> to zero has no effect.

373

To change request to GET, you should use <a class="emphasis" href="#CURLOPTHTTPGET">CURLOPT_HTTPGET</a>. Change request to POST with <a class="emphasis" href="#CURLOPTPOST">CURLOPT_POST</a> etc.

353

374

<a name="CURLOPTINFILESIZE"></a>CURLOPT_INFILESIZE

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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 <a class="emphasis" href="#CURLOPTINFILESIZELARGE">CURLOPT_INFILESIZE_LARGE</a>.

355

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<a name="CURLOPTINFILESIZELARGE"></a>CURLOPT_INFILESIZE_LARGE

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381

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 <a class="emphasis" href="#CURLOPTHTTPHEADER">CURLOPT_HTTPHEADER</a>. With HTTP 1.0 or without chunked transfer, you must specify the size.

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382

<a name="CURLOPTMAXFILESIZE"></a>CURLOPT_MAXFILESIZE

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383

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.

363

NOTE: 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.

384

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.

364

385

<a name="CURLOPTMAXFILESIZELARGE"></a>CURLOPT_MAXFILESIZE_LARGE

365

386

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)

366

387

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388

<a name="CURLOPTTIMECONDITION"></a>CURLOPT_TIMECONDITION

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389

Pass a long as parameter. This defines how the <a class="emphasis" href="#CURLOPTTIMEVALUE">CURLOPT_TIMEVALUE</a> time value is treated. You can set this parameter to CURL_TIMECOND_IFMODSINCE or CURL_TIMECOND_IFUNMODSINCE. This feature applies to HTTP and FTP.

369

NOTE: 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.

390

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.

370

391

<a name="CURLOPTTIMEVALUE"></a>CURLOPT_TIMEVALUE

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392

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 <a class="emphasis" href="#CURLOPTTIMECONDITION">CURLOPT_TIMECONDITION</a>. <a name="CONNECTION"></a><h2 class="nroffsh">CONNECTION OPTIONS</h2>

372

393

373

394

<a name="CURLOPTTIMEOUT"></a>CURLOPT_TIMEOUT

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395

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.

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NOTE: this is not recommended to use in unix multi-threaded programs, as it uses signals unless <a class="emphasis" href="#CURLOPTNOSIGNAL">CURLOPT_NOSIGNAL</a> (see above) is set.

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In unix-like systems, this might cause signals to be used unless <a class="emphasis" href="#CURLOPTNOSIGNAL">CURLOPT_NOSIGNAL</a> is set.

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<a name="CURLOPTLOWSPEEDLIMIT"></a>CURLOPT_LOW_SPEED_LIMIT

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Pass a long as parameter. It contains the transfer speed in bytes per second that the transfer should be below during <a class="emphasis" href="#CURLOPTLOWSPEEDTIME">CURLOPT_LOW_SPEED_TIME</a> seconds for the library to consider it too slow and abort.

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399

<a name="CURLOPTLOWSPEEDTIME"></a>CURLOPT_LOW_SPEED_TIME

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401

<a name="CURLOPTMAXCONNECTS"></a>CURLOPT_MAXCONNECTS

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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. 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 persistent connections.

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When reaching the maximum limit, curl uses the <a class="emphasis" href="#CURLOPTCLOSEPOLICY">CURLOPT_CLOSEPOLICY</a> to figure out which of the existing connections to close to prevent the number of open connections to increase.

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

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

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<a name="CURLOPTCLOSEPOLICY"></a>CURLOPT_CLOSEPOLICY

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Pass a long. This option sets what policy libcurl should use when the connection cache is filled and one of the open connections has to be closed to make room for a new connection. This must be one of the CURLCLOSEPOLICY_* defines. Use CURLCLOSEPOLICY_LEAST_RECENTLY_USED to make libcurl close the connection that was least recently used, that connection is also least likely to be capable of re-use. Use CURLCLOSEPOLICY_OLDEST to make libcurl close the oldest connection, the one that was created first among the ones in the connection cache. The other close policies are not support yet.

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<a name="CURLOPTFRESHCONNECT"></a>CURLOPT_FRESH_CONNECT

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Pass a long. Set to non-zero to make the next transfer explicitly close the connection 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).

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<a name="CURLOPTCONNECTTIMEOUT"></a>CURLOPT_CONNECTTIMEOUT

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Pass a long. It should contain the maximum time in seconds that you allow the connection 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 <a class="emphasis" href="#CURLOPTTIMEOUT">CURLOPT_TIMEOUT</a> option.

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413

In unix-like systems, this might cause signals to be used unless <a class="emphasis" href="#CURLOPTNOSIGNAL">CURLOPT_NOSIGNAL</a> is set.

393

414

<a name="CURLOPTIPRESOLVE"></a>CURLOPT_IPRESOLVE

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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:

395

416

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433

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 <a class="emphasis" href="#CURLOPTSSLKEYTYPE">CURLOPT_SSLKEYTYPE</a>.

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434

<a name="CURLOPTSSLKEYTYPE"></a>CURLOPT_SSLKEYTYPE

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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".

415

NOTE: The format "ENG" enables you to load the private key from a crypto engine. In this case <a class="emphasis" href="#CURLOPTSSLKEY">CURLOPT_SSLKEY</a> is used as an identifier passed to the engine. You have to set the crypto engine with <a class="emphasis" href="#CURLOPTSSLENGINE">CURLOPT_SSLENGINE</a>. "DER" format key file currently does not work because of a bug in OpenSSL.

436

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

416

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<a name="CURLOPTSSLKEYPASSWD"></a>CURLOPT_SSLKEYPASSWD

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Pass a pointer to a zero terminated string as parameter. It will be used as the password required to use the <a class="emphasis" href="#CURLOPTSSLKEY">CURLOPT_SSLKEY</a> private key.

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<a name="CURLOPTSSLENGINE"></a>CURLOPT_SSLENGINE

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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.

420

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

441

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

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442

<a name="CURLOPTSSLENGINEDEFAULT"></a>CURLOPT_SSLENGINE_DEFAULT

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443

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

423

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

444

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

424

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<a name="CURLOPTSSLVERSION"></a>CURLOPT_SSLVERSION

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

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447

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470

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.

450

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<a name="CURLOPTSSLVERIFYHOST"></a>CURLOPT_SSL_VERIFYHOST

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Pass a long as parameter.

452

This option determines whether curl verifies that the server claims to be who you want it to be.

473

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

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

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When <a class="emphasis" href="#CURLOPTSSLVERIFYHOST">CURLOPT_SSL_VERIFYHOST</a> is 2, that certificate must indicate that the server is the server to which you meant to connect, or the connection fails.

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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.

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