curl_setopt

(PHP 4 >= 4.0.2, PHP 5, PHP 7)

Set an option for a cURL transfer

bool curl_setopt ( resource $ch, int $option, mixed $value )

Sets an option on the given cURL session handle.

Parameters:

A cURL handle returned by curl_init().

option

The CURLOPT_XXX option to set.

value

The value to be set on option.

value should be a bool for the following values of the option parameter:

Option	Set `value` to	Notes
`CURLOPT_AUTOREFERER`	`TRUE` to automatically set the Referer: field in requests where it follows a Location: redirect.
`CURLOPT_BINARYTRANSFER`	`TRUE` to return the raw output when `CURLOPT_RETURNTRANSFER` is used.	From PHP 5.1.3, this option has no effect: the raw output will always be returned when `CURLOPT_RETURNTRANSFER` is used.
`CURLOPT_COOKIESESSION`	`TRUE` 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 or not. Session cookies are cookies without expiry date and they are meant to be alive and existing for this "session" only.
`CURLOPT_CERTINFO`	`TRUE` to output SSL certification information to STDERR on secure transfers.	Added in cURL 7.19.1. Available since PHP 5.3.2. Requires `CURLOPT_VERBOSE` to be on to have an effect.
`CURLOPT_CONNECT_ONLY`	`TRUE` tells the library to perform all the required proxy authentication and connection setup, but no data transfer. This option is implemented for HTTP, SMTP and POP3.	Added in 7.15.2. Available since PHP 5.5.0.
`CURLOPT_CRLF`	`TRUE` to convert Unix newlines to CRLF newlines on transfers.
`CURLOPT_DNS_USE_GLOBAL_CACHE`	`TRUE` to use a global DNS cache. This option is not thread-safe and is enabled by default.
`CURLOPT_FAILONERROR`	`TRUE` to fail verbosely if the HTTP code returned is greater than or equal to 400. The default behavior is to return the page normally, ignoring the code.
`CURLOPT_FILETIME`	`TRUE` to attempt to retrieve the modification date of the remote document. This value can be retrieved using the `CURLINFO_FILETIME` option with curl_getinfo().
`CURLOPT_FOLLOWLOCATION`	`TRUE` to follow any "Location: " header that the server sends as part of the HTTP header (note this is recursive, PHP will follow as many "Location: " headers that it is sent, unless `CURLOPT_MAXREDIRS` is set).
`CURLOPT_FORBID_REUSE`	`TRUE` to force the connection to explicitly close when it has finished processing, and not be pooled for reuse.
`CURLOPT_FRESH_CONNECT`	`TRUE` to force the use of a new connection instead of a cached one.
`CURLOPT_FTP_USE_EPRT`	`TRUE` to use EPRT (and LPRT) when doing active FTP downloads. Use `FALSE` to disable EPRT and LPRT and use PORT only.
`CURLOPT_FTP_USE_EPSV`	`TRUE` to first try an EPSV command for FTP transfers before reverting back to PASV. Set to `FALSE` to disable EPSV.
`CURLOPT_FTP_CREATE_MISSING_DIRS`	`TRUE` to create missing directories when an FTP operation encounters a path that currently doesn't exist.
`CURLOPT_FTPAPPEND`	`TRUE` to append to the remote file instead of overwriting it.
`CURLOPT_TCP_NODELAY`	`TRUE` to disable TCP's Nagle algorithm, which tries to minimize the number of small packets on the network.	Available since PHP 5.2.1 for versions compiled with libcurl 7.11.2 or greater.
`CURLOPT_FTPASCII`	An alias of `CURLOPT_TRANSFERTEXT`. Use that instead.
`CURLOPT_FTPLISTONLY`	`TRUE` to only list the names of an FTP directory.
`CURLOPT_HEADER`	`TRUE` to include the header in the output.
`CURLINFO_HEADER_OUT`	`TRUE` to track the handle's request string.	Available since PHP 5.1.3. The `CURLINFO_` prefix is intentional.
`CURLOPT_HTTPGET`	`TRUE` to reset the HTTP request method to GET. Since GET is the default, this is only necessary if the request method has been changed.
`CURLOPT_HTTPPROXYTUNNEL`	`TRUE` to tunnel through a given HTTP proxy.
`CURLOPT_MUTE`	`TRUE` to be completely silent with regards to the cURL functions.	Removed in cURL 7.15.5 (You can use CURLOPT_RETURNTRANSFER instead)
`CURLOPT_NETRC`	`TRUE` to scan the `~/.netrc` file to find a username and password for the remote site that a connection is being established with.
`CURLOPT_NOBODY`	`TRUE` to exclude the body from the output. Request method is then set to HEAD. Changing this to `FALSE` does not change it to GET.
`CURLOPT_NOPROGRESS`	`TRUE` to disable the progress meter for cURL transfers. Note: PHP automatically sets this option to `TRUE`, this should only be changed for debugging purposes.
`CURLOPT_NOSIGNAL`	`TRUE` to ignore any cURL function that causes a signal to be sent to the PHP process. This is turned on by default in multi-threaded SAPIs so timeout options can still be used.	Added in cURL 7.10.
`CURLOPT_POST`	`TRUE` to do a regular HTTP POST. This POST is the normal application/x-www-form-urlencoded kind, most commonly used by HTML forms.
`CURLOPT_PUT`	`TRUE` to HTTP PUT a file. The file to PUT must be set with `CURLOPT_INFILE` and `CURLOPT_INFILESIZE`.
`CURLOPT_RETURNTRANSFER`	`TRUE` to return the transfer as a string of the return value of curl_exec() instead of outputting it out directly.
`CURLOPT_SAFE_UPLOAD`	`TRUE` to disable support for the @ prefix for uploading files in `CURLOPT_POSTFIELDS`, which means that values starting with @ can be safely passed as fields. CURLFile may be used for uploads instead.	Added in PHP 5.5.0 with `FALSE` as the default value. PHP 5.6.0 changes the default value to `TRUE`.
`CURLOPT_SSL_VERIFYPEER`	`FALSE` to stop cURL from verifying the peer's certificate. Alternate certificates to verify against can be specified with the `CURLOPT_CAINFO` option or a certificate directory can be specified with the `CURLOPT_CAPATH` option.	`TRUE` by default as of cURL 7.10. Default bundle installed as of cURL 7.10.
`CURLOPT_TRANSFERTEXT`	`TRUE` to use ASCII mode for FTP transfers. For LDAP, it retrieves data in plain text instead of HTML. On Windows systems, it will not set STDOUT to binary mode.
`CURLOPT_UNRESTRICTED_AUTH`	`TRUE` to keep sending the username and password when following locations (using `CURLOPT_FOLLOWLOCATION`), even when the hostname has changed.
`CURLOPT_UPLOAD`	`TRUE` to prepare for an upload.
`CURLOPT_VERBOSE`	`TRUE` to output verbose information. Writes output to STDERR, or the file specified using `CURLOPT_STDERR`.

value should be an integer for the following values of the option parameter:

Option	Set `value` to	Notes
`CURLOPT_BUFFERSIZE`	The size of the buffer to use for each read. There is no guarantee this request will be fulfilled, however.	Added in cURL 7.10.
`CURLOPT_CLOSEPOLICY`	One of the *`CURLCLOSEPOLICY_` values. Note**: This option is deprecated, as it was never implemented in cURL and never had any effect.	Removed in PHP 5.6.0.
`CURLOPT_CONNECTTIMEOUT`	The number of seconds to wait while trying to connect. Use 0 to wait indefinitely.
`CURLOPT_CONNECTTIMEOUT_MS`	The number of milliseconds to wait while trying to connect. Use 0 to wait indefinitely. If libcurl is built to use the standard system name resolver, that portion of the connect will still use full-second resolution for timeouts with a minimum timeout allowed of one second.	Added in cURL 7.16.2. Available since PHP 5.2.3.
`CURLOPT_DNS_CACHE_TIMEOUT`	The number of seconds to keep DNS entries in memory. This option is set to 120 (2 minutes) by default.
`CURLOPT_FTPSSLAUTH`	The FTP authentication method (when is activated): CURLFTPAUTH_SSL (try SSL first), CURLFTPAUTH_TLS (try TLS first), or CURLFTPAUTH_DEFAULT (let cURL decide).	Added in cURL 7.12.2.
`CURLOPT_HTTP_VERSION`	`CURL_HTTP_VERSION_NONE` (default, lets CURL decide which version to use), `CURL_HTTP_VERSION_1_0` (forces HTTP/1.0), or `CURL_HTTP_VERSION_1_1` (forces HTTP/1.1).
`CURLOPT_HTTPAUTH`	The HTTP authentication method(s) to use. The options are: `CURLAUTH_BASIC`, `CURLAUTH_DIGEST`, `CURLAUTH_GSSNEGOTIATE`, `CURLAUTH_NTLM`, `CURLAUTH_ANY`, and `CURLAUTH_ANYSAFE`. The bitwise \| (or) operator can be used to combine more than one method. If this is done, cURL will poll the server to see what methods it supports and pick the best one. `CURLAUTH_ANY` is an alias for CURLAUTH_BASIC \| CURLAUTH_DIGEST \| CURLAUTH_GSSNEGOTIATE \| CURLAUTH_NTLM. `CURLAUTH_ANYSAFE` is an alias for CURLAUTH_DIGEST \| CURLAUTH_GSSNEGOTIATE \| CURLAUTH_NTLM.
`CURLOPT_INFILESIZE`	The expected size, in bytes, of the file when uploading a file to a remote site. Note that using this option will not stop libcurl from sending more data, as exactly what is sent depends on `CURLOPT_READFUNCTION`.
`CURLOPT_LOW_SPEED_LIMIT`	The transfer speed, in bytes per second, that the transfer should be below during the count of `CURLOPT_LOW_SPEED_TIME` seconds before PHP considers the transfer too slow and aborts.
`CURLOPT_LOW_SPEED_TIME`	The number of seconds the transfer speed should be below `CURLOPT_LOW_SPEED_LIMIT` before PHP considers the transfer too slow and aborts.
`CURLOPT_MAXCONNECTS`	The maximum amount of persistent connections that are allowed. When the limit is reached, `CURLOPT_CLOSEPOLICY` is used to determine which connection to close.
`CURLOPT_MAXREDIRS`	The maximum amount of HTTP redirections to follow. Use this option alongside `CURLOPT_FOLLOWLOCATION`.
`CURLOPT_PORT`	An alternative port number to connect to.
`CURLOPT_POSTREDIR`	A bitmask of 1 (301 Moved Permanently), 2 (302 Found) and 4 (303 See Other) if the HTTP POST method should be maintained when `CURLOPT_FOLLOWLOCATION` is set and a specific type of redirect occurs.	Added in cURL 7.19.1. Available since PHP 5.3.2.
`CURLOPT_PROTOCOLS`	Bitmask of *`CURLPROTO_` values. If used, this bitmask limits 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 transfers to only be allowed to use a subset of them. By default libcurl will accept all protocols it supports. See also `CURLOPT_REDIR_PROTOCOLS`**. Valid protocol options are: `CURLPROTO_HTTP`, `CURLPROTO_HTTPS`, `CURLPROTO_FTP`, `CURLPROTO_FTPS`, `CURLPROTO_SCP`, `CURLPROTO_SFTP`, `CURLPROTO_TELNET`, `CURLPROTO_LDAP`, `CURLPROTO_LDAPS`, `CURLPROTO_DICT`, `CURLPROTO_FILE`, `CURLPROTO_TFTP`, `CURLPROTO_ALL`	Added in cURL 7.19.4.
`CURLOPT_PROXYAUTH`	The HTTP authentication method(s) to use for the proxy connection. Use the same bitmasks as described in `CURLOPT_HTTPAUTH`. For proxy authentication, only `CURLAUTH_BASIC` and `CURLAUTH_NTLM` are currently supported.	Added in cURL 7.10.7.
`CURLOPT_PROXYPORT`	The port number of the proxy to connect to. This port number can also be set in `CURLOPT_PROXY`.
`CURLOPT_PROXYTYPE`	Either `CURLPROXY_HTTP` (default), `CURLPROXY_SOCKS4`, `CURLPROXY_SOCKS5`, `CURLPROXY_SOCKS4A` or `CURLPROXY_SOCKS5_HOSTNAME`.	Added in cURL 7.10.
`CURLOPT_REDIR_PROTOCOLS`	Bitmask of *`CURLPROTO_` values. If used, this bitmask limits 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. See also `CURLOPT_PROTOCOLS`** for protocol constant values.	Added in cURL 7.19.4.
`CURLOPT_RESUME_FROM`	The offset, in bytes, to resume a transfer from.
`CURLOPT_SSL_VERIFYHOST`	1 to check the existence of a common name in the SSL peer certificate. 2 to check the existence of a common name and also verify that it matches the hostname provided. In production environments the value of this option should be kept at 2 (default value).	Support for value 1 removed in cURL 7.28.1
`CURLOPT_SSLVERSION`	One of `CURL_SSLVERSION_DEFAULT` (0), `CURL_SSLVERSION_TLSv1` (1), `CURL_SSLVERSION_SSLv2` (2), `CURL_SSLVERSION_SSLv3` (3), `CURL_SSLVERSION_TLSv1_0` (4), `CURL_SSLVERSION_TLSv1_1` (5) or `CURL_SSLVERSION_TLSv1_2` (6). Note: Your best bet is to not set this and let it use the default. Setting it to 2 or 3 is very dangerous given the known vulnerabilities in SSLv2 and SSLv3.
`CURLOPT_TIMECONDITION`	How `CURLOPT_TIMEVALUE` is treated. Use `CURL_TIMECOND_IFMODSINCE` to return the page only if it has been modified since the time specified in `CURLOPT_TIMEVALUE`. If it hasn't been modified, a "304 Not Modified" header will be returned assuming `CURLOPT_HEADER` is `TRUE`. Use `CURL_TIMECOND_IFUNMODSINCE` for the reverse effect. `CURL_TIMECOND_IFMODSINCE` is the default.
`CURLOPT_TIMEOUT`	The maximum number of seconds to allow cURL functions to execute.
`CURLOPT_TIMEOUT_MS`	The maximum number of milliseconds to allow cURL functions to execute. If libcurl is built to use the standard system name resolver, that portion of the connect will still use full-second resolution for timeouts with a minimum timeout allowed of one second.	Added in cURL 7.16.2. Available since PHP 5.2.3.
`CURLOPT_TIMEVALUE`	The time in seconds since January 1st, 1970. The time will be used by `CURLOPT_TIMECONDITION`. By default, `CURL_TIMECOND_IFMODSINCE` is used.
`CURLOPT_MAX_RECV_SPEED_LARGE`	If a download exceeds this speed (counted in bytes per second) 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 cURL 7.15.5. Available since PHP 5.4.0.
`CURLOPT_MAX_SEND_SPEED_LARGE`	If an upload exceeds this speed (counted in bytes per second) 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 cURL 7.15.5. Available since PHP 5.4.0.
`CURLOPT_SSH_AUTH_TYPES`	A bitmask consisting of one or more of `CURLSSH_AUTH_PUBLICKEY`, `CURLSSH_AUTH_PASSWORD`, `CURLSSH_AUTH_HOST`, `CURLSSH_AUTH_KEYBOARD`. Set to `CURLSSH_AUTH_ANY` to let libcurl pick one.	Added in cURL 7.16.1.
`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, possible values are `CURL_IPRESOLVE_WHATEVER`, `CURL_IPRESOLVE_V4`, `CURL_IPRESOLVE_V6`, by default `CURL_IPRESOLVE_WHATEVER`.	Added in cURL 7.10.8.

value should be a string for the following values of the option parameter:

Option	Set `value` to	Notes
`CURLOPT_CAINFO`	The name of a file holding one or more certificates to verify the peer with. This only makes sense when used in combination with `CURLOPT_SSL_VERIFYPEER`.	Might require an absolute path.
`CURLOPT_CAPATH`	A directory that holds multiple CA certificates. Use this option alongside `CURLOPT_SSL_VERIFYPEER`.
`CURLOPT_COOKIE`	The contents of the "Cookie: " header to be used in the HTTP request. Note that multiple cookies are separated with a semicolon followed by a space (e.g., "fruit=apple; colour=red")
`CURLOPT_COOKIEFILE`	The name of the file containing the cookie data. The cookie file can be in Netscape format, or just plain HTTP-style headers dumped into a file. If the name is an empty string, no cookies are loaded, but cookie handling is still enabled.
`CURLOPT_COOKIEJAR`	The name of a file to save all internal cookies to when the handle is closed, e.g. after a call to curl_close.
`CURLOPT_CUSTOMREQUEST`	A custom request method to use instead of "GET" or "HEAD" when doing a HTTP request. This is useful for doing "DELETE" or other, more obscure HTTP requests. Valid values are things like "GET", "POST", "CONNECT" and so on; i.e. Do not enter a whole HTTP request line here. For instance, entering "GET /index.html HTTP/1.0\r\n\r\n" would be incorrect. Note: Don't do this without making sure the server supports the custom request method first.
`CURLOPT_EGDSOCKET`	Like `CURLOPT_RANDOM_FILE`, except a filename to an Entropy Gathering Daemon socket.
`CURLOPT_ENCODING`	The contents of the "Accept-Encoding: " header. This enables decoding of the response. Supported encodings are "identity", "deflate", and "gzip". If an empty string, "", is set, a header containing all supported encoding types is sent.	Added in cURL 7.10.
`CURLOPT_FTPPORT`	The value which 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 hostname, a network interface name (under Unix), or just a plain '-' to use the systems default IP address.
`CURLOPT_INTERFACE`	The name of the outgoing network interface to use. This can be an interface name, an IP address or a host name.
`CURLOPT_KEYPASSWD`	The password required to use the `CURLOPT_SSLKEY` or `CURLOPT_SSH_PRIVATE_KEYFILE` private key.	Added in cURL 7.16.1.
`CURLOPT_KRB4LEVEL`	The KRB4 (Kerberos 4) security level. Any of the following values (in order from least to most powerful) are valid: "clear", "safe", "confidential", "private".. If the string does not match one of these, "private" is used. Setting this option to `NULL` will disable KRB4 security. Currently KRB4 security only works with FTP transactions.
`CURLOPT_POSTFIELDS`	The full data to post in a HTTP "POST" operation. To post a file, prepend a filename with @ and use the full path. The filetype can be explicitly specified by following the filename with the type in the format ';type=mimetype'. This parameter can either be passed as a urlencoded string like 'para1=val1&para2=val2&...' or as an array with the field name as key and field data as value. If `value` is an array, the Content-Type header will be set to multipart/form-data. As of PHP 5.2.0, `value` must be an array if files are passed to this option with the @ prefix. As of PHP 5.5.0, the @ prefix is deprecated and files can be sent using CURLFile. The @ prefix can be disabled for safe passing of values beginning with @ by setting the `CURLOPT_SAFE_UPLOAD` option to `TRUE`.
`CURLOPT_PROXY`	The HTTP proxy to tunnel requests through.
`CURLOPT_PROXYUSERPWD`	A username and password formatted as "[username]:[password]" to use for the connection to the proxy.
`CURLOPT_RANDOM_FILE`	A filename to be used to seed the random number generator for SSL.
`CURLOPT_RANGE`	Range(s) of data to retrieve in the format "X-Y" where X or Y are optional. HTTP transfers also support several intervals, separated with commas in the format "X-Y,N-M".
`CURLOPT_REFERER`	The contents of the "Referer: " header to be used in a HTTP request.
`CURLOPT_SSH_HOST_PUBLIC_KEY_MD5`	A string containing 32 hexadecimal digits. The string should be the MD5 checksum 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 cURL 7.17.1.
`CURLOPT_SSH_PUBLIC_KEYFILE`	The file name for your public key. If not used, libcurl defaults to $HOME/.ssh/id_dsa.pub if the HOME environment variable is set, and just "id_dsa.pub" in the current directory if HOME is not set.	Added in cURL 7.16.1.
`CURLOPT_SSH_PRIVATE_KEYFILE`	The file name for your private key. If not used, libcurl defaults to $HOME/.ssh/id_dsa if the HOME environment variable is set, and just "id_dsa" in the current directory if HOME is not set. If the file is password-protected, set the password with `CURLOPT_KEYPASSWD`.	Added in cURL 7.16.1.
`CURLOPT_SSL_CIPHER_LIST`	A list of ciphers to use for SSL. For example, RC4-SHA and TLSv1 are valid cipher lists.
`CURLOPT_SSLCERT`	The name of a file containing a PEM formatted certificate.
`CURLOPT_SSLCERTPASSWD`	The password required to use the `CURLOPT_SSLCERT` certificate.
`CURLOPT_SSLCERTTYPE`	The format of the certificate. Supported formats are "PEM" (default), "DER", and "ENG".	Added in cURL 7.9.3.
`CURLOPT_SSLENGINE`	The identifier for the crypto engine of the private SSL key specified in `CURLOPT_SSLKEY`.
`CURLOPT_SSLENGINE_DEFAULT`	The identifier for the crypto engine used for asymmetric crypto operations.
`CURLOPT_SSLKEY`	The name of a file containing a private SSL key.
`CURLOPT_SSLKEYPASSWD`	The secret password needed to use the private SSL key specified in `CURLOPT_SSLKEY`. Note: Since this option contains a sensitive password, remember to keep the PHP script it is contained within safe.
`CURLOPT_SSLKEYTYPE`	The key type of the private SSL key specified in `CURLOPT_SSLKEY`. Supported key types are "PEM" (default), "DER", and "ENG".
`CURLOPT_URL`	The URL to fetch. This can also be set when initializing a session with curl_init().
`CURLOPT_USERAGENT`	The contents of the "User-Agent: " header to be used in a HTTP request.
`CURLOPT_USERPWD`	A username and password formatted as "[username]:[password]" to use for the connection.

value should be an array for the following values of the option parameter:

Option	Set `value` to	Notes
`CURLOPT_HTTP200ALIASES`	An array of HTTP 200 responses that will be treated as valid responses and not as errors.	Added in cURL 7.10.3.
`CURLOPT_HTTPHEADER`	An array of HTTP header fields to set, in the format `array('Content-type: text/plain', 'Content-length: 100')`
`CURLOPT_POSTQUOTE`	An array of FTP commands to execute on the server after the FTP request has been performed.
`CURLOPT_QUOTE`	An array of FTP commands to execute on the server prior to the FTP request.

value should be a stream resource (using fopen(), for example) for the following values of the option parameter:

Option	Set `value` to
`CURLOPT_FILE`	The file that the transfer should be written to. The default is STDOUT (the browser window).
`CURLOPT_INFILE`	The file that the transfer should be read from when uploading.
`CURLOPT_STDERR`	An alternative location to output errors to instead of STDERR.
`CURLOPT_WRITEHEADER`	The file that the header part of the transfer is written to.

value should be the name of a valid function or a Closure for the following values of the option parameter:

Option	Set `value` to
`CURLOPT_HEADERFUNCTION`	A callback accepting two parameters. The first is the cURL resource, the second is a string with the header data to be written. The header data must be written by this callback. Return the number of bytes written.
`CURLOPT_PASSWDFUNCTION`	A callback accepting three parameters. The first is the cURL resource, the second is a string containing a password prompt, and the third is the maximum password length. Return the string containing the password.
`CURLOPT_PROGRESSFUNCTION`	A callback accepting five parameters. The first is the cURL resource, the second is the total number of bytes expected to be downloaded in this transfer, the third is the number of bytes downloaded so far, the fourth is the total number of bytes expected to be uploaded in this transfer, and the fifth is the number of bytes uploaded so far. Note: The callback is only called when the `CURLOPT_NOPROGRESS` option is set to `FALSE`. Return a non-zero value to abort the transfer. In which case, the transfer will set a `CURLE_ABORTED_BY_CALLBACK` error.
`CURLOPT_READFUNCTION`	A callback accepting three parameters. The first is the cURL resource, the second is a stream resource provided to cURL through the option `CURLOPT_INFILE`, and the third is the maximum amount of data to be read. The callback must return a string with a length equal or smaller than the amount of data requested, typically by reading it from the passed stream resource. It should return an empty string to signal EOF.
`CURLOPT_WRITEFUNCTION`	A callback accepting two parameters. The first is the cURL resource, and the second is a string with the data to be written. The data must be saved by this callback. It must return the exact number of bytes written or the transfer will be aborted with an error.

Other values:

Option	Set `value` to
`CURLOPT_SHARE`	A result of curl_share_init(). Makes the cURL handle to use the data from the shared handle.

Returns:

Returns TRUE on success or FALSE on failure.

Changelog:

5.6.0

CURLOPT_SAFE_UPLOAD TRUE

5.6.0

Removed CURLOPT_CLOSEPOLICY and associated values.

5.5.0

Added the cURL resource as the first argument to the CURLOPT_PROGRESSFUNCTION callback.

5.5.0

Introduced CURLOPT_SHARE.

5.3.0

Introduced CURLOPT_PROGRESSFUNCTION.

5.2.10

Introduced CURLOPT_PROTOCOLS, and CURLOPT_REDIR_PROTOCOLS.

5.1.0

Introduced CURLOPT_AUTOREFERER, CURLOPT_BINARYTRANSFER, CURLOPT_FTPSSLAUTH, CURLOPT_PROXYAUTH, and CURLOPT_TIMECONDITION.

5.0.0

Introduced CURLOPT_FTP_USE_EPRT, CURLOPT_NOSIGNAL, CURLOPT_UNRESTRICTED_AUTH, CURLOPT_BUFFERSIZE, CURLOPT_HTTPAUTH, CURLOPT_PROXYPORT, CURLOPT_PROXYTYPE, CURLOPT_SSLCERTTYPE, and CURLOPT_HTTP200ALIASES.

Notes:

Passing an array to CURLOPT_POSTFIELDS will encode the data as multipart/form-data, while passing a URL-encoded string will encode the data as application/x-www-form-urlencoded.

Examples:

Initializing a new cURL session and fetching a web page

<?php
// create a new cURL resource
$ch = curl_init();

// set URL and other appropriate options
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch, CURLOPT_HEADER, false);

// grab URL and pass it to the browser
curl_exec($ch);

// close cURL resource, and free up system resources
curl_close($ch);
?>

Uploading file (deprecated as of PHP 5.5.0)

<?php

/* http://localhost/upload.php:
print_r($_POST);
print_r($_FILES);
*/

$ch = curl_init();

$data = array('name' => 'Foo', 'file' => '@/home/user/test.png');

curl_setopt($ch, CURLOPT_URL, 'http://localhost/upload.php');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_SAFE_UPLOAD, false); // required as of PHP 5.6.0
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

curl_exec($ch);
?>

The above example will output:

Array
(
    [name] => Foo
)
Array
(
    [file] => Array
        (
            [name] => test.png
            [type] => image/png
            [tmp_name] => /tmp/phpcpjNeQ
            [error] => 0
            [size] => 279
        )

)