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);
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).
NOTES
Including <sys/time.h> is not required these days, but increases porta‐
bility. (Indeed, <sys/resource.h> defines the rusage structure with
fields of type struct timeval defined in <sys/time.h>.)
The prototype for these functions is only available if _BSD_SOURCE is
defined.
CONFORMING TO
4.3BSD
SEE ALSOfork(2), getrusage(2), sigaction(2), signal(2), wait(2), signal(7)Linux 2004-11-11 WAIT4(2)
