|| Linux Programmer's Manual
NAME getpid, getppid - get process identification
() returns the process ID of the calling process. (This is often used by routines that generate unique temporary filenames.)
() returns the process ID of the parent of the calling process.
ERRORS These functions are always successful.
CONFORMING TO POSIX.1-2001, 4.3BSD, SVr4.
NOTES 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
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.
COLOPHON This page is part of release 3.53 of the Linux
man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.