NAME¶

sys/wait.h - declarations for waiting

SYNOPSIS¶

#include <sys/wait.h>

DESCRIPTION¶

The <sys/wait.h> header shall define the following symbolic constants for use with waitpid():

WNOHANG

Do not hang if no status is available; return immediately.

WUNTRACED

Report status of stopped child process.

The <sys/wait.h> header shall define 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 shall be defined as possible values for the options argument to waitid():

WEXITED

Wait for processes that have exited.

WSTOPPED

Status is returned for any child that has stopped upon receipt of a signal.

WCONTINUED

Status is 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 shall be defined as an enumeration type whose possible values shall include at least the following: P_ALL P_PID P_PGID

The id_t and pid_t types shall be defined as described in <sys/types.h> .

The siginfo_t type shall be defined as described in <signal.h> .

The rusage structure shall be defined as described in <sys/resource.h> .

Inclusion of the <sys/wait.h> header may also make visible all symbols from <signal.h> and <sys/resource.h>.

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

pid_t  wait(int *);
int    waitid(idtype_t, id_t, siginfo_t *, int);
pid_t  waitpid(pid_t, int *, int);

The following sections are informative.

APPLICATION USAGE¶

None.

RATIONALE¶

None.

FUTURE DIRECTIONS¶

None.

SEE ALSO¶

<signal.h>, <sys/resource.h>, <sys/types.h>, the System Interfaces volume of IEEE Std 1003.1-2001, wait(), waitid()

COPYRIGHT¶

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .