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authorDaniel Stenberg <daniel@haxx.se>2014-10-09 13:17:27 +0200
committerDaniel Stenberg <daniel@haxx.se>2014-10-09 13:17:27 +0200
commit93b268ade0cc2be0329f1e4e891b01e38ae2c1e7 (patch)
tree592e0a8dbce4be9931a1aee0f551add711f51592
parent9e37a7f9a5cd141c717aa0262e8dee7713c25200 (diff)
curl_multi_fdset: explain the fd_set arguments
-rw-r--r--docs/libcurl/curl_multi_fdset.324
1 files changed, 18 insertions, 6 deletions
diff --git a/docs/libcurl/curl_multi_fdset.3 b/docs/libcurl/curl_multi_fdset.3
index 3dbdc4504..5e5ab9492 100644
--- a/docs/libcurl/curl_multi_fdset.3
+++ b/docs/libcurl/curl_multi_fdset.3
@@ -5,7 +5,7 @@
.\" * | (__| |_| | _ <| |___
.\" * \___|\___/|_| \_\_____|
.\" *
-.\" * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
@@ -37,8 +37,20 @@ 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
\fIcurl_multi_fdset(3)\fP only adds its own descriptors, it doesn't zero or
-otherwise remove any others. The \fIcurl_multi_perform(3)\fP function should be
-called as soon as one of them is ready to be read from or written to.
+otherwise remove any others. The \fIcurl_multi_perform(3)\fP function should
+be called as soon as one of them is ready to be read from or written to.
+
+If the \fIread_fd_set\fP argument is not a null pointer, it points to an
+object of type fd_set that on returns specifies the file descriptors to be
+checked for being ready to read.
+
+If the \fIwrite_fd_set\fP argument is not a null pointer, it points to an
+object of type fd_set that on return specifies the file descriptors to be
+checked for being ready to write.
+
+If the \fIexc_fd_set\fP argument is not a null pointer, it points to an object
+of type fd_set that on return specifies the file descriptors to be checked for
+error conditions pending.
If no file descriptors are set by libcurl, \fImax_fd\fP will contain -1 when
this function returns. Otherwise it will contain the higher descriptor number
@@ -47,8 +59,8 @@ currently does something that isn't possible for your application to monitor
with a socket and unfortunately you can then not know exactly when the current
action is completed using select(). When max_fd returns with -1, you need to
wait a while and then proceed and call \fIcurl_multi_perform\fP anyway. How
-long to wait? I would suggest 100 milliseconds at least, but you may want to
-test it out in your own particular conditions to find a suitable value.
+long to wait? We suggest 100 milliseconds at least, but you may want to test
+it out in your own particular conditions to find a suitable value.
When doing select(), you should use \fBcurl_multi_timeout\fP to figure out how
long to wait for action. Call \fIcurl_multi_perform\fP even if no activity has
@@ -67,4 +79,4 @@ CURLMcode type, general libcurl multi interface error code. See
\fIlibcurl-errors(3)\fP
.SH "SEE ALSO"
.BR curl_multi_cleanup "(3), " curl_multi_init "(3), "
-.BR curl_multi_timeout "(3), " curl_multi_perform "(3) "
+.BR curl_multi_timeout "(3), " curl_multi_perform "(3), " select "(2) "