getpid(2) - phpMan

GETPID(2)                  Linux Programmer's Manual                 GETPID(2)



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.  Nor-
       mally 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  get-
       pid()  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  get-
       pid()  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 3.22 of the Linux man-pages project.  A description of
       the project, and information about reporting bugs, can be found at  http://www.ker-
       nel.org/doc/man-pages/.



Linux                             2008-09-23                         GETPID(2)

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