clarified that you must keep the variables that you point to!

docs/libcurl/curl_multi_fdset.3

@@ -1,6 +1,6 @@
 .\" $Id$
 .\"
-.TH curl_multi_fdset 3 "1 March 2002" "libcurl 7.9.5" "libcurl Manual"
+.TH curl_multi_fdset 3 "3 May 2002" "libcurl 7.9.5" "libcurl Manual"
 .SH NAME
 curl_multi_fdset - add an easy handle to a multi session
 .SH SYNOPSIS
@@ -17,6 +17,10 @@ This function extracts file descriptor information from a given multi_handle.
 libcurl returns its fd_set sets. The application can use these to select() or
 poll() on. The curl_multi_perform() function should be called as soon as one
 of them are ready to be read from or written to.
+
+NOTE that once this call is made, you must not remove the sets you point to,
+as libcurl will need to be able to read them. It needs them after select()
+calls, to know if certain sockets are readable or writable.
 .SH RETURN VALUE
 CURLMcode type, general libcurl multi interface error code.
 .SH "SEE ALSO"