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

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       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.