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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 || _XOPEN_SOURCE >= 500 ||
           _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
       wait4():
           _BSD_SOURCE

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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