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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.  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 dis-
       cussion 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),  tmp-
       file(3),	tmpnam(3), credentials(7), pid_namespaces(7)

COLOPHON
       This page is part of release 3.74 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
       http://www.kernel.org/doc/man-pages/.

Linux				  2014-09-21			     GETPID(2)

NAME | SYNOPSIS | DESCRIPTION | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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