wait3, wait4 - wait for process to change state, BSD style
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/wait.h>
pid_t wait3(int *wstatus, int options,
struct rusage *rusage);
pid_t wait4(pid_t pid, int *wstatus, int options,
struct rusage *rusage);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
wait3():
Since glibc 2.19:
_DEFAULT_SOURCE || _XOPEN_SOURCE >= 500
Glibc 2.19 and earlier:
_BSD_SOURCE || _XOPEN_SOURCE >= 500
wait4():
Since glibc 2.19:
_DEFAULT_SOURCE
Glibc 2.19 and earlier:
_BSD_SOURCE
These functions are nonstandard; in new programs, the use of
waitpid(2)
or
waitid(2) is preferable.
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(wstatus, options, rusage);
is equivalent to:
waitpid(-1, wstatus, options);
Similarly, the following
wait4() call:
wait4(pid, wstatus, options, rusage);
is equivalent to:
waitpid(pid, wstatus, 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.
As for
waitpid(2).
As for
waitpid(2).
4.3BSD.
SUSv1 included a specification of
wait3(); SUSv2 included
wait3(),
but marked it LEGACY; SUSv3 removed it.
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.
fork(2),
getrusage(2),
sigaction(2),
signal(2),
wait(2),
signal(7)