from small one page howto to huge articles all in one place
 

search text in:





Poll
What does your sytem tell when running "ulimit -u"?








poll results

Last additions:
using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

109244

userrating:

average rating: 1.7 (85 votes) (1=very good 6=terrible)


May 25th. 2007:
Words

486

Views

223266

why adblockers are bad


Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

103540

userrating:

average rating: 1.3 (28 votes) (1=very good 6=terrible)


April, 26th. 2006:

Druckversion
You are here: manpages





GETPID

Section: Linux Programmer's Manual (2)
Updated: 2017-05-03
Index Return to Main Contents
 

NAME

getpid, getppid - get process identification  

SYNOPSIS

#include <sys/types.h>
#include <unistd.h>

pid_t getpid(void);
pid_t getppid(void);  

DESCRIPTION

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. This will be either the ID of the process that created this process using fork(), or, if that process has already terminated, the ID of the process to which this process has been reparented (either init(1) or a "subreaper" process defined via the prctl(2) PR_SET_CHILD_SUBREAPER operation).  

ERRORS

These functions are always successful.  

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, 4.3BSD, SVr4.  

NOTES

If the caller's parent is in a different PID namespace (see pid_namespaces(7)), getppid() returns 0.  

C library/kernel differences

From glibc version 2.3.4 up to and including version 2.24, the glibc wrapper function for getpid() cached PIDs, with the goal of avoiding additional system calls when a process calls getpid() repeatedly. Normally this caching was invisible, but its correct operation relied on support in the wrapper functions for fork(2), vfork(2), and clone(2): if an application bypassed the glibc wrappers for these system calls by using syscall(2), then a call to getpid() in the child would return the wrong value (to be precise: it would return the PID of the parent process). In addition, there were cases where getpid() could return the wrong value even when invoking clone(2) via the glibc wrapper function. (For a discussion of one such case, see BUGS in clone(2).) Furthermore, the complexity of the caching code had been the source of a few bugs within glibc over the years.

Because of the aforementioned problems, since glibc version 2.25, the PID cache is removed: calls to getpid() always invoke the actual system call, rather than returning a cached value.  

SEE ALSO

clone(2), fork(2), kill(2), exec(3), mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3), credentials(7), pid_namespaces(7)  

COLOPHON

This page is part of release 4.13 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
ERRORS
CONFORMING TO
NOTES
C library/kernel differences
SEE ALSO
COLOPHON


Please read "Why adblockers are bad".



Other free services
toURL.org
Shorten long
URLs to short
links like
http://tourl.org/2
tourl.org
.
Reverse DNS lookup
Find out which hostname(s)
resolve to a
given IP or other hostnames for the server
www.reversednslookup.org
rdf newsfeed | rss newsfeed | Atom newsfeed
- Powered by LeopardCMS - Running on Gentoo -
Copyright 2004-2017 Sascha Nitsch Unternehmensberatung UG(haftungsbeschränkt)
Valid XHTML1.1 : Valid CSS : buttonmaker
- Level Triple-A Conformance to Web Content Accessibility Guidelines 1.0 -
- Copyright and legal notices -
Time to create this page: 3.3 ms