wait3, wait4 — wait for process to change state, BSD style
#define _BSD_SOURCE /* Or #define _XOPEN_SOURCE 500 for wait3() */ #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) ; |
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.
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>
.)
fork(2), getrusage(2), sigaction(2), signal(2), wait(2), feature_test_macros(7), signal(7)
|