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.

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 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.

SEE ALSO

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

COLOPHON

       This page is part of release 3.54 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/.

Linux                                              2008-09-23                                          GETPID(2)