wait4(2)

1WAIT4(2)                   Linux Programmer's Manual                  WAIT4(2)
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NAME

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

9       #define _BSD_SOURCE
10                       /* Or #define _XOPEN_SOURCE 500 for wait3() */
11       #include <sys/types.h>
12       #include <sys/time.h>
13       #include <sys/resource.h>
14       #include <sys/wait.h>
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16       pid_t wait3(int *status, int options,
17             struct rusage *rusage);
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19       pid_t wait4(pid_t pid, int *status, int options,
20             struct rusage *rusage);
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DESCRIPTION

23       The  wait3()  and  wait4()  system calls are similar to waitpid(2), but
24       additionally return resource usage information about the child  in  the
25       structure pointed to by rusage.
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27       Other than the use of the rusage argument, the following wait3() call:
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29           wait3(status, options, rusage);
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31       is equivalent to:
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33           waitpid(-1, status, options);
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35       Similarly, the following wait4() call:
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37           wait4(pid, status, options, rusage);
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39       is equivalent to:
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41           waitpid(pid, status, options);
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43       In  other  words, wait3() waits of any child, while wait4() can be used
44       to select a specific child, or children, on which to wait.  See wait(2)
45       for further details.
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47       If  rusage  is  not  NULL, the struct rusage to which it points will be
48       filled with accounting information about the child.   See  getrusage(2)
49       for details.
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RETURN VALUE

52       As for waitpid(2).
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ERRORS

55       As for waitpid(2).
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NOTES

58       Including <sys/time.h> is not required these days, but increases porta‐
59       bility.  (Indeed, <sys/resource.h> defines the  rusage  structure  with
60       fields of type struct timeval defined in <sys/time.h>.)
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CONFORMING TO

63       4.3BSD
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