Unknown options are now checked for every pid, with 0x80 and 0x80000040 added, and so are valid combinations such as WNOHANG | WUNTRACED. Each call is repeated with a null status. The TechnicalDebt entry cites kern_wait, which adds WEXITED and WTRAPPED, and lists pdfork.
waitpid returns -1 with ECHILD, or EINVAL for an option FreeBSD does not know, and leaves the status unwritten: AnyPS5 runs the title as one process and exports nothing that creates a child. VLC PPSA85300 stops on main at this import.
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