sys/wait.h - declarations for waiting
The <sys/wait.h> header shall define the following symbolic constants
for use with waitpid():
Do not hang if no status is available; return immediately.
Report status of stopped child process.
The <sys/wait.h> header shall define the following macros for analysis
of process status values:
Return exit status.
True if child has been continued.
True if child exited normally.
True if child exited due to uncaught signal.
True if child is currently stopped.
Return signal number that caused process to stop.
Return signal number that caused process to terminate.
The following symbolic constants shall be defined as possible values
for the options argument to waitid():
Wait for processes that have exited.
Status is returned for any child that has stopped upon receipt
of a signal.
Status is returned for any child that was stopped and has been
Return immediately if there are no children to wait for.
Keep the process whose status is returned in infop in a waitable
The type idtype_t shall be defined as an enumeration type whose
possible values shall include at least the following: P_ALL P_PID
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.
<signal.h> , <sys/resource.h> , <sys/types.h> , the System Interfaces
volume of IEEE Std 1003.1-2001, wait(), waitid()
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 .