GETPID

 

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).