- Make curl_multi_waitfds consistent with the documentation.
Issue Addressed:
- The documentation of curl_multi_waitfds indicates that users should
be able to call curl_multi_waitfds with a NULL ufds. However, before
this change, the function would return CURLM_BAD_FUNCTION_ARGUMENT.
- Additionally, the documentation suggests that users can use this
function to determine the number of file descriptors (fds) needed.
However, the function would stop counting fds if the supplied fds
were exhausted.
Changes Made:
- NULL ufds Handling: curl_multi_waitfds can now accept a NULL ufds if
size is also zero.
- Counting File Descriptors: If curl_multi_waitfds is passed a NULL
ufds, or the size of ufds is insufficient, the output parameter
fd_count will return the number of fds needed. This value may be
higher than actually needed but never lower.
Testing:
- Test 2405 has been updated to cover the usage scenarios described
above.
Fixes https://github.com/curl/curl/issues/15146
Closes https://github.com/curl/curl/pull/15155
Before this patch, the result code was a mixture of `int` and
`CURLcode`.
Also adjust casts and fix a couple of minor issues found along the way.
Cherry-picked from #13489Closes#13600
