Standard C Library (libc, -lc)

The getpid system call returns the process ID of the calling process. Though the ID is guaranteed to be unique, it should NOT be used for constructing temporary file names, for security reasons; see mkstemp(3) instead.

The getppid system call returns the process ID of the parent of the calling process.

The getpid and getppid system calls are always successful, and no return value is reserved to indicate an error.

fork(2), getpgrp(2), kill(2), setpgid(2), setsid(2), exec(3)

The getpid and getppid system calls are expected to conform to ISO/IEC 9945-1:1990 ("POSIX.1")

The getpid function appeared in