append
Adds a file descriptor to @list.
The file descriptor is duplicated using dup(). You keep your copy of the descriptor and the copy contained in @list will be closed when @list is finalized.
A possible cause of failure is exceeding the per-process or system-wide file descriptor limit.
The index of the file descriptor in the list is returned. If you use this index with g_unix_fd_list_get() then you will receive back a duplicated copy of the same file descriptor.
Return
the index of the appended fd in case of success, else -1 (and @error is set)
Since
2.24
Parameters
fd
a valid open file descriptor