NAME

curl_multi_socket - reads/writes available data

SYNOPSIS

#include <curl/curl.h>
CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t sockfd,
                            int *running_handles);
CURLMcode curl_multi_socket_all(CURLM *multi_handle,
                                int *running_handles);

DESCRIPTION

These functions are deprecated. Do not use. See curl_multi_socket_action(3) instead.

At return, the integer running_handles points to contains the number of still running easy handles within the multi handle. When this number reaches zero, all transfers are complete/done. Note that when you call curl_multi_socket_action(3) on a specific socket and the counter decreases by one, it DOES NOT necessarily mean that this exact socket/transfer is the one that completed. Use curl_multi_info_read(3) to figure out which easy handle that completed.

The curl_multi_socket_action(3) functions inform the application about updates in the socket (file descriptor) status by doing none, one, or multiple calls to the socket callback function set with the CURLMOPT_SOCKETFUNCTION(3) option to curl_multi_setopt(3). They update the status with changes since the previous time the callback was called.

Get the timeout time by setting the CURLMOPT_TIMERFUNCTION(3) option with curl_multi_setopt(3). Your application then gets called with information on how long to wait for socket actions at most before doing the timeout action: call the curl_multi_socket_action(3) function with the sockfd argument set to CURL_SOCKET_TIMEOUT. You can also use the curl_multi_timeout(3) function to poll the value at any given time, but for an event-based system using the callback is far better than relying on polling the timeout value.

Usage of curl_multi_socket(3) is deprecated, whereas the function is equivalent to curl_multi_socket_action(3) with ev_bitmask set to 0.

Force libcurl to (re-)check all its internal sockets and transfers instead of just a single one by calling curl_multi_socket_all(3). Note that there should not be any reason to use this function.

EXAMPLE

int main(void)
{
  /* the event-library gets told when there activity on the socket 'fd',
     which we translate to a call to curl_multi_socket_action() */
  int running;
  int rc;
  int fd;
  CURLM *multi;
  rc = curl_multi_socket(multi, fd, &running);
}

AVAILABILITY

This function was added in libcurl 7.15.4, and is deemed stable since 7.16.0.

curl_multi_socket(3) is deprecated, use curl_multi_socket_action(3) instead!

RETURN VALUE

CURLMcode type, general libcurl multi interface error code.