NAME¶
CURLOPT_SOCKOPTFUNCTION - set callback for setting socket options
SYNOPSIS¶
#include <curl/curl.h>
typedef enum {
CURLSOCKTYPE_IPCXN, /* socket created for a specific IP connection */
CURLSOCKTYPE_ACCEPT, /* socket created by accept() call */
CURLSOCKTYPE_LAST /* never use */
} curlsocktype;
#define CURL_SOCKOPT_OK 0
#define CURL_SOCKOPT_ERROR 1 /* causes libcurl to abort and return
CURLE_ABORTED_BY_CALLBACK */
#define CURL_SOCKOPT_ALREADY_CONNECTED 2
int sockopt_callback(void *clientp,
curl_socket_t curlfd,
curlsocktype purpose);
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
DESCRIPTION¶
Pass a pointer to your callback function, which should match the prototype shown
above.
When set, this callback function gets called by libcurl when the socket has been
created, but before the connect call to allow applications to change specific
socket options. The callback's
purpose argument identifies the exact
purpose for this particular socket:
CURLSOCKTYPE_IPCXN for actively created connections or since 7.28.0
CURLSOCKTYPE_ACCEPT for FTP when the connection was setup with
PORT/EPSV (in earlier versions these sockets weren't passed to this callback).
Future versions of libcurl may support more purposes. libcurl passes the newly
created socket descriptor to the callback in the
curlfd parameter so
additional setsockopt() calls can be done at the user's discretion.
The
clientp pointer contains whatever user-defined value set using the
CURLOPT_SOCKOPTDATA(3) function.
Return
CURL_SOCKOPT_OK from the callback on success. Return
CURL_SOCKOPT_ERROR from the callback function to signal an
unrecoverable error to the library and it will close the socket and return
CURLE_COULDNT_CONNECT. Alternatively, the callback function can return
CURL_SOCKOPT_ALREADY_CONNECTED, to tell libcurl that the socket is
already connected and then libcurl will not attempt to connect it. This allows
an application to pass in an already connected socket with
CURLOPT_OPENSOCKETFUNCTION(3) and then have this function make libcurl
not attempt to connect (again).
DEFAULT¶
By default, this callback is NULL and unused.
PROTOCOLS¶
All
EXAMPLE¶
TODO
AVAILABILITY¶
Added in 7.16.0. The
CURL_SOCKOPT_ALREADY_CONNECTED return code was added
in 7.21.5.
RETURN VALUE¶
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
SEE ALSO¶
CURLOPT_SOCKOPTDATA(3),
CURLOPT_OPENSOCKETFUNCTION(3),