setpgid()--Set Process Group ID for Job Control

 #include <sys/types.h>
 #include <unistd.h>

 int setpgid(pid_t pid, pid_t pgid);  

The setpgid() function is used to either join an existing process group or create a new process group within the session of the calling process.

See the Usage Notes for considerations in using setpgid().

Parameters

pid

(Input) The process ID of the process whose process group ID is to be changed. When pid has a value of zero, the process group ID of the calling process is changed.

pgid

(Input) The process group ID to be assigned to the process whose process ID matches pid. The value of pgid must be within the range of zero through the maximum signed integer. When pgid/em> has a value of zero, the process group ID is set to the process ID of the process indicated by pid.

Authorities

The process calling setpgid() must have the appropriate authority to the process being changed. A process is allowed to access the process group ID for a process if at least one of the following conditions is true:

• The process is calling setpgid() for its own process.
  
  
• The process has *JOBCTL special authority defined in the process user profile or in a current adopted user profile.
  
  
• The process is the parent of the process (the process being examined has a parent process ID equal to the process ID of the process calling setpgid()).
  
  
• The real or effective user ID of the process matches the real or effective user ID of the process calling setpgid()).

Return Value

Error Conditions

If setpgid() is not successful, errno usually indicates one of the following errors. Under some conditions, errno could indicate an error other than that listed here.

[EINVAL]

The value specified for the argument is not correct.

A function was passed incorrect argument values, or an operation was attempted on an object and the operation specified is not supported for that type of object.

An argument value is not valid, out of range, or NULL.

[EPERM]

Operation not permitted.

You must have appropriate privileges or be the owner of the object or other resource to do the requested operation.

[ESRCH]

No item could be found that matches the specified value.

Usage Notes

1. i5/OS does not support sessions. Until session support is available on i5/OS, the restriction that the process group must be within the session of the calling process will not be enforced.
   
   
2. The setpgid() function fails if a nonzero process group ID is specified and that process group does not exist. If this occurs, the return value is set to -1 and errno is set to [EPERM].

Related Information

• The <sys/types.h> file (see Header Files for UNIX-Type Functions)
  
  
• The <unistd.h> file (see Header Files for UNIX-Type Functions)
  
  
• getpgrp()--Get Process Group ID
  
  
• Qp0wGetPgrp()--Get Process Group ID