oracular (3) curl_multi_timeout.3.gz

NAME

       curl_multi_timeout - how long to wait for action before proceeding

SYNOPSIS

       #include <curl/curl.h>

       CURLMcode curl_multi_timeout(CURLM *multi_handle, long *timeout);

DESCRIPTION

       An application using the libcurl multi interface should call curl_multi_timeout(3) to figure out how long
       it should wait for socket actions - at most - before proceeding.

       Proceeding means either doing the  socket-style  timeout  action:  call  the  curl_multi_socket_action(3)
       function  with  the  sockfd argument set to CURL_SOCKET_TIMEOUT, or call curl_multi_perform(3) if you are
       using the simpler and older multi interface approach.

       The timeout value returned in the long timeout points to, is in number of milliseconds at this moment. If
       0,  it  means  you should proceed immediately without waiting for anything. If it returns -1, there is no
       timeout at all set.

       An application that uses the multi_socket API should not use this function.  It should  instead  use  the
       CURLMOPT_TIMERFUNCTION(3) option for proper and desired behavior.

       Note:  if  libcurl  returns a -1 timeout here, it just means that libcurl currently has no stored timeout
       value. You must not wait too long (more than a few seconds perhaps) before you call curl_multi_perform(3)
       again.

PROTOCOLS

       This functionality affects all supported protocols

EXAMPLE

       int main(void)
       {
         struct timeval timeout;
         long timeo;
         fd_set fdread;
         fd_set fdwrite;
         fd_set fdexcep;
         int maxfd;
         CURLM *multi = curl_multi_init();

         curl_multi_timeout(multi, &timeo);
         if(timeo < 0)
           /* no set timeout, use a default */
           timeo = 980;

         timeout.tv_sec = timeo / 1000;
         timeout.tv_usec = (timeo % 1000) * 1000;

         /* wait for activities no longer than the set timeout */
         select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
       }

TYPICAL USAGE

       Call  curl_multi_timeout(3), then wait for action on the sockets. Figure out which sockets to wait for by
       calling curl_multi_fdset(3).

       When there is activity or timeout, call curl_multi_perform(3) and then loop -  until  all  transfers  are
       complete.

AVAILABILITY

       Added in curl 7.15.4

RETURN VALUE

       The standard CURLMcode for multi interface error codes.

SEE ALSO

       curl_multi_fdset(3), curl_multi_info_read(3), curl_multi_setopt(3), curl_multi_socket(3)