Adds a file descriptor to message.
The file descriptor is duplicated using dup(). You keep your copy
of the descriptor and the copy contained in message will be closed
when message is finalized.
A possible cause of failure is exceeding the per-process or
system-wide file descriptor limit.
Since 2.22
Adds a file descriptor to message. The file descriptor is duplicated using dup(). You keep your copy of the descriptor and the copy contained in message will be closed when message is finalized. A possible cause of failure is exceeding the per-process or system-wide file descriptor limit. Since 2.22