GETPID(2) System Calls GETPID(2)
NAME
getpid, getpgrp, getppid, getpgid - get process, process group, and
parent process IDs
SYNOPSIS
#include <unistd.h>
pid_t getpid(
void);
pid_t getpgrp(
void);
pid_t getppid(
void);
pid_t getpgid(
pid_t pid);
DESCRIPTION
The
getpid() function returns the process
ID of the calling process.
The
getpgrp() function returns the process group
ID of the calling
process.
The
getppid() function returns the parent process
ID of the calling
process.
The
getpgid() function returns the process group
ID of the process whose
process
ID is equal to
pid, or the process group
ID of the calling
process, if
pid is equal to 0.
RETURN VALUES
The
getpid(),
getpgrp(), and
getppid() functions are always successful
and no return value is reserved to indicate an error.
Upon successful completion,
getpgid() returns the process group ID.
Otherwise,
getpgid() returns
(pid_t)-1 and sets
errno to indicate the
error.
ERRORS
The
getpgid() function will fail if:
EPERM The process whose process
ID is equal to
pid is not in the same
session as the calling process, and the implementation does not
allow access to the process group
ID of that process from the
calling process.
ESRCH There is no process with a process
ID equal to
pid.
The
getpgid() function may fail if:
EINVAL The value of the
pid argument is invalid.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|MT-Level | Async-Signal-Safe |
+--------------------+-------------------+
|Standard | See
standards(7). |
+--------------------+-------------------+
SEE ALSO
Intro(2),
exec(2),
fork(2),
getsid(2),
setpgid(2),
setpgrp(2),
setsid(2),
signal(3C),
attributes(7),
standards(7) January 27, 2009
GETPID(2)