getpgid()
QNX SDP8.0C Library ReferenceAPIDeveloper
Get a process group ID
Synopsis:
#include <unistd.h>
pid_t getpgid( pid_t pid );
Arguments:
- pid
 - The ID of the process whose process group ID you want to get.
 
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The getpgid() returns the group ID for the process specified by pid. If pid is 0, getpgid() returns the calling process's group ID.
Note: 
In order to get the group ID of a process outside the calling process's
session, your process must have the
PROCMGR_AID_GETID ability enabled.
For more information, see
procmgr_ability().
The following definitions are worth mentioning:
- Process
 - An executing instance of a program, identified by a nonnegative integer called a process ID.
 - Process group
 - A collection of one or more processes, with a unique process group ID. A process group ID is a positive integer.
 
Returns:
A process group ID for success, or (pid_t)-1 if an error occurred (errno is set).
Errors:
- EPERM
 - The calling process doesn't have the required permission; see procmgr_ability().
 - ESRCH
 - The process specified by pid doesn't exist.
 
Classification:
| Safety: | |
|---|---|
| Cancellation point | No | 
| Signal handler | Yes | 
| Thread | Yes | 
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