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)