sys/wait.h是函式聲明，方便庫函式調用。
基本介紹
- 外文名：sys/wait.h
- 類別：函式聲明
- 作用：方便庫函式調用
NAMEsys/wait.h - declarations for waitingSYNOPSIS
#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.
[pre]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()
CHANGE HISTORY
First released in Issue 3.
Included for alignment with the POSIX.1-1988 standard.
Issue 6
The wait3() function is removed.
