filter_wait - wrap waitpid to decode the exitcode and why your filter quit

       pid -> the process identifier to wait for
       options -> the options to pass to waitpid (see wait(2))

       filter_wait  wraps the waitpid call and raises an error (with description) if the call failed.  Note that
       if the ask for the exitcode and the process exited with a code other than zero, we don't raise an  error.
       If you don't ask for the exitcode, and it is non-zero, we raise an error

       filter_wait  - wrap waitpid to decode the exitcode and why your filter quit

       exitcode -> the exitcode if the process existed normally

filter_wait(3), filter_create_fp(3), filter_create_fd

ClearSilver                                       12 July 2007                                    filter_wait(3)

       #include <util/filter.h>

       NEOERR *filter_wait(pid_t pid, int options, int *exitcode);