getpid, getppid — get process identification
#include <sys/types.h> #include <unistd.h>
pid_t
getpid( |
void); |
pid_t
getppid( |
void); |
getpid() returns the process
ID of the calling process. (This is often used by routines
that generate unique temporary filenames.)
getppid() returns the
process ID of the parent of the calling process.
If the caller's parent is in a different PID namespace
(see pid_namespaces(7)),
getppid() returns 0.
Since glibc version 2.3.4, the glibc wrapper function
for getpid() caches PIDs, so
as to avoid additional system calls when a process calls
getpid() repeatedly. Normally
this caching is invisible, but its correct operation relies
on support in the wrapper functions for fork(2), vfork(2), and clone(2): if an
application bypasses the glibc wrappers for these system
calls by using syscall(2), then a call
to getpid() in the child will
return the wrong value (to be precise: it will return the
PID of the parent process). See also clone(2) for discussion
of a case where getpid() may
return the wrong value even when invoking clone(2) via the glibc
wrapper function.
clone(2), fork(2), kill(2), exec(3), mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3), credentials(7), pid_namespaces(7)
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright 1993 Rickard E. Faith (faithcs.unc.edu) %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END |