1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: curl_multi_timeout 5Section: 3 6Source: libcurl 7See-also: 8 - curl_multi_fdset (3) 9 - curl_multi_info_read (3) 10 - curl_multi_setopt (3) 11 - curl_multi_socket (3) 12Protocol: 13 - All 14--- 15 16# NAME 17 18curl_multi_timeout - how long to wait for action before proceeding 19 20# SYNOPSIS 21 22~~~c 23#include <curl/curl.h> 24 25CURLMcode curl_multi_timeout(CURLM *multi_handle, long *timeout); 26~~~ 27 28# DESCRIPTION 29 30An application using the libcurl multi interface should call 31curl_multi_timeout(3) to figure out how long it should wait for socket 32actions - at most - before proceeding. 33 34Proceeding means either doing the socket-style timeout action: call the 35curl_multi_socket_action(3) function with the **sockfd** argument set 36to CURL_SOCKET_TIMEOUT, or call curl_multi_perform(3) if you are using 37the simpler and older multi interface approach. 38 39The timeout value returned in the long **timeout** points to, is in number 40of milliseconds at this moment. If 0, it means you should proceed immediately 41without waiting for anything. If it returns -1, there is no timeout at all set. 42 43An application that uses the *multi_socket* API should not use this function. 44It should instead use the CURLMOPT_TIMERFUNCTION(3) option for proper and 45desired behavior. 46 47Note: if libcurl returns a -1 timeout here, it just means that libcurl 48currently has no stored timeout value. You must not wait too long (more than a 49few seconds perhaps) before you call curl_multi_perform(3) again. 50 51# EXAMPLE 52 53~~~c 54int main(void) 55{ 56 struct timeval timeout; 57 long timeo; 58 fd_set fdread; 59 fd_set fdwrite; 60 fd_set fdexcep; 61 int maxfd; 62 CURLM *multi = curl_multi_init(); 63 64 curl_multi_timeout(multi, &timeo); 65 if(timeo < 0) 66 /* no set timeout, use a default */ 67 timeo = 980; 68 69 timeout.tv_sec = timeo / 1000; 70 timeout.tv_usec = (timeo % 1000) * 1000; 71 72 /* wait for activities no longer than the set timeout */ 73 select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout); 74} 75~~~ 76 77# TYPICAL USAGE 78 79Call curl_multi_timeout(3), then wait for action on the sockets. Figure 80out which sockets to wait for by calling curl_multi_fdset(3). 81 82When there is activity or timeout, call curl_multi_perform(3) and then 83loop - until all transfers are complete. 84 85# AVAILABILITY 86 87This function was added in libcurl 7.15.4. 88 89# RETURN VALUE 90 91The standard CURLMcode for multi interface error codes. 92
