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

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

       This  page is part of release 3.27 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								    2010-09-20								  WAIT4(2)