curl_multi_fdset(3) libcurl Manual curl_multi_fdset(3)NAMEcurl_multi_fdset - extracts file descriptor information from a multi
CURLMcode curl_multi_fdset(CURLM *multi_handle,
This function extracts file descriptor information from a given
multi_handle. libcurl returns its fd_set sets. The application can use
these to select() on, but be sure to FD_ZERO them before calling this
function as curl_multi_fdset(3) only adds its own descriptors, it
doesn't zero or otherwise remove any others. The curl_multi_perform(3)
function should be called as soon as one of them is ready to be read
from or written to.
If no file descriptors are set by libcurl, max_fd will contain -1 when
this function returns. Otherwise it will contain the higher descriptor
number libcurl set.
You should also be aware that when doing select(), you should consider
using a rather small (single-digit number of seconds) timeout and call
curl_multi_perform regularly - even if no activity has been seen on the
fd_sets - as otherwise libcurl-internal retries and timeouts may not
work as you'd think and want.
Starting with libcurl 7.16.0, you should use curl_multi_timeout to fig‐
ure out how long to wait for action.
CURLMcode type, general libcurl multi interface error code. See
libcurl-errors(3)SEE ALSOcurl_multi_cleanup(3),curl_multi_init(3), curl_multi_timeout(3)libcurl 7.16.0 2 Jan 2006 curl_multi_fdset(3)