NAME
sys/wait.h —
declarations for waiting
SYNOPSIS
#include <sys/wait.h>
DESCRIPTION
The <sys/wait.h> header defines the
following symbolic constants for use with waitpid(3) :
- WNOHANG
- Do not hang if no status is available, return immediately.
- WUNTRACED
- Report status of stopped child process.
and the following macros for analysis of process status values:
- WEXITSTATUS()
- Return exit status.
- WIFCONTINUED()
- True if child has been continued
- WIFEXITED()
- True if child exited normally.
- WIFSIGNALED()
- True if child exited due to uncaught signal.
- WIFSTOPPED()
- True if child is currently stopped.
- WSTOPSIG()
- Return signal number that caused process to stop.
- WTERMSIG()
- Return signal number that caused process to terminate.
The following symbolic constants are defined as possible values for the options argument to waitid():
- WEXITED
- Wait for processes that have exited.
- WSTOPPED
- Status will be returned for any child that has stopped upon receipt of a signal.
- WCONTINUED
- Status will be returned for any child that was stopped and has been continued.
- WNOHANG
- Return immediately if there are no children to wait for.
- WNOWAIT
- Keep the process whose status is returned in infop in a waitable state.
The type idtype_t is defined as an enumeration type whose possible values include at least the following: P_ALL P_PID P_PGID
The id_t type is defined as described in <sys/types.h>.
The siginfo_t type is defined as described in <signal.h>.
The rusage structure is defined as described in <sys/resource.h>.
The pid_t type is defined as described in <sys/types.h>.
Inclusion of the <sys/wait.h> header may also make visible all symbols from <signal.h> and <sys/resource.h>.
The following are declared as functions and may also be defined as
macros. Function prototypes must be provided for use with an ISO C compiler.
pid_t wait(int *); pid_t wait3(int *, int, struct rusage
*); int waitid(idtype_t, id_t, siginfo_t *, int); pid_t waitpid(pid_t, int
*, int);
APPLICATION USAGE
None.
FUTURE DIRECTIONS
None.