1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: curl_multi_socket 5Section: 3 6Source: libcurl 7See-also: 8 - curl_multi_cleanup (3) 9 - curl_multi_fdset (3) 10 - curl_multi_info_read (3) 11 - curl_multi_init (3) 12 - the hiperfifo.c example 13Protocol: 14 - All 15Added-in: 7.15.4 16--- 17 18# NAME 19 20curl_multi_socket - read/write available data 21 22# SYNOPSIS 23 24~~~c 25#include <curl/curl.h> 26CURLMcode curl_multi_socket(CURLM *multi_handle, curl_socket_t sockfd, 27 int *running_handles); 28~~~ 29 30# DESCRIPTION 31 32This function is deprecated. Use curl_multi_socket_action(3) instead with 33**ev_bitmask** set to 0. 34 35At return, the integer **running_handles** points to contains the number of 36still running easy handles within the multi handle. When this number reaches 37zero, all transfers are complete/done. Note that when you call 38curl_multi_socket(3) on a specific socket and the counter decreases by one, it 39DOES NOT necessarily mean that this exact socket/transfer is the one that 40completed. Use curl_multi_info_read(3) to figure out which easy handle that 41completed. 42 43The curl_multi_socket(3) functions inform the application about updates in the 44socket (file descriptor) status by doing none, one, or multiple calls to the 45socket callback function set with the CURLMOPT_SOCKETFUNCTION(3) option to 46curl_multi_setopt(3). They update the status with changes since the previous 47time the callback was called. 48 49Get the timeout time by setting the CURLMOPT_TIMERFUNCTION(3) option with 50curl_multi_setopt(3). Your application then gets called with information on 51how long to wait for socket actions at most before doing the timeout action: 52call the curl_multi_socket_action(3) function with the **sockfd** argument set 53to CURL_SOCKET_TIMEOUT. You can also use the curl_multi_timeout(3) function to 54poll the value at any given time, but for an event-based system using the 55callback is far better than relying on polling the timeout value. 56 57# %PROTOCOLS% 58 59# EXAMPLE 60 61~~~c 62int main(void) 63{ 64 /* the event-library gets told when there activity on the socket 'fd', 65 which we translate to a call to curl_multi_socket_action() */ 66 int running; 67 int rc; 68 int fd; 69 CURLM *multi; 70 rc = curl_multi_socket(multi, fd, &running); 71} 72~~~ 73 74# DEPRECATED 75 76curl_multi_socket(3) is deprecated, use curl_multi_socket_action(3) instead. 77 78# %AVAILABILITY% 79 80# RETURN VALUE 81 82This function returns a CURLMcode indicating success or error. 83 84CURLM_OK (0) means everything was OK, non-zero means an error occurred, see 85libcurl-errors(3). 86 87The return code is for the whole multi stack. Problems still might have 88occurred on individual transfers even when one of these functions return OK. 89