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 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), cre‐
       dentials(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)