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NAME

       wait3, wait4 - wait for process to change state, BSD style

SYNOPSIS

       #include <sys/types.h>
       #include <sys/time.h>
       #include <sys/resource.h>
       #include <sys/wait.h>

       pid_t wait3(int *status, int options,
                   struct rusage *rusage);

       pid_t wait4(pid_t pid, int *status, int options,
                   struct rusage *rusage);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       wait3(): _BSD_SOURCE
       wait4(): _BSD_SOURCE || _XOPEN_SOURCE >= 500

DESCRIPTION

       The  wait3()  and  wait4()  system calls are similar to waitpid(2), but
       additionally return resource usage information about the child  in  the
       structure pointed to by rusage.

       Other than the use of the rusage argument, the following wait3() call:

           wait3(status, options, rusage);

       is equivalent to:

           waitpid(-1, status, options);

       Similarly, the following wait4() call:

           wait4(pid, status, options, rusage);

       is equivalent to:

           waitpid(pid, status, options);

       In  other  words, wait3() waits of any child, while wait4() can be used
       to select a specific child, or children, on which to wait.  See wait(2)
       for further details.

       If  rusage  is  not  NULL, the struct rusage to which it points will be
       filled with accounting information about the child.   See  getrusage(2)
       for details.

RETURN VALUE

       As for waitpid(2).

ERRORS

       As for waitpid(2).

CONFORMING TO

       4.3BSD.

NOTES

       Including  <sys/time.h>  is  not  required  these  days,  but increases
       portability.  (Indeed, <sys/resource.h> defines  the  rusage  structure
       with fields of type struct timeval defined in <sys/time.h>.)

       On  Linux,  wait3()  is  a  library  function implemented on top of the
       wait4() system call.

SEE ALSO

       fork(2), getrusage(2), sigaction(2), signal(2), wait(2), signal(7)

COLOPHON

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