Front Page

libcurl index

---

C API Front

Tutorial

Error Codes

All Functions

easy Interface

multi Interface

share Interface

---

curl_multi_add_handle

curl_multi_assign

curl_multi_cleanup

curl_multi_fdset

curl_multi_info_read

curl_multi_init

curl_multi_perform

curl_multi_remove_handle

curl_multi_setopt

curl_multi_socket

curl_multi_socket_action

curl_multi_strerror

curl_multi_timeout

Sponsors:
Haxx

curl_multi_fdset.3 -- man page

NAME

curl_multi_fdset - extracts file descriptor information from a multi handle

SYNOPSIS

#include <curl/curl.h>
 
CURLMcode curl_multi_fdset(CURLM *multi_handle,
                            fd_set *read_fd_set,
                            fd_set *write_fd_set,
                            fd_set *exc_fd_set,
                            int *max_fd);
 

DESCRIPTION

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.

To be sure to have up-to-date results, you should call curl_multi_perform until it does not return CURLM_CALL_MULTI_PERFORM prior to calling curl_multi_fdset. This will make sure that libcurl has updated the handles' socket states.

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 figure out how long to wait for action.

RETURN VALUE

CURLMcode type, general libcurl multi interface error code. See libcurl-errors(3)

SEE ALSO

curl_multi_cleanup (3) curl_multi_init (3) curl_multi_timeout (3) curl_multi_perform (3)

This HTML page was made with roffit.