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WAIT4(2)                   Linux Programmer's Manual                  WAIT4(2)



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

SYNOPSIS
       #include <&lt;sys/types.h>&gt;
       #include <&lt;sys/time.h>&gt;
       #include <&lt;sys/resource.h>&gt;
       #include <&lt;sys/wait.h>&gt;

       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 &lt;sys/time.h&gt; is not required these days, but increases porta-
       bility.  (Indeed, &lt;sys/resource.h&gt; defines the  rusage  structure  with
       fields of type struct timeval defined in &lt;sys/time.h&gt;.)

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

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux                             2007-07-26                          WAIT4(2)