setpgid(2)							System Calls Manual							setpgid(2)

NAME

       setpgid, setpgrp - Sets the process group ID

SYNOPSIS

       #include <unistd.h>

       int setpgid(
	       pid_t process_id,
	       pid_t process_group_id);

	pid_t setpgrp(void);

       Application  developers	may  want  to  specify an #include statement for <sys/types.h> before the one for <unistd.h> if programs are being
       developed for multiple platforms. The additional #include statement is not required on Tru64 UNIX systems or by ISO  or	X/Open	standards,
       but may be required on other vendors' systems that conform to these standards.

       The following alternate declaration for setpgrp() does not conform to current standards and is supported only for backward compatibility:

	int setpgrp(
	       pid_t process_id,
	       pid_t process_group_id);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       setpgid(): XSH5.0

       setpgrp(): SVID 3, XSH5.0

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

PARAMETERS

       Specifies the ID of the process whose process group ID is to be changed.  Specifies the new process group ID.

DESCRIPTION

       Use  the setpgid() function to add a process to an existing process group or to create a new process group within a process's session.  The
       setpgid() function does not change the process group ID of a session leader.

       The setpgid() function sets the process group ID of the process identified by the process_id parameter. The process group ID is set to  the
       value specified in the process_group_id parameter.

       If  the	process_id parameter contains 0 (zero), the setpgid() function sets the process group ID of the calling process.  The new value of
       the process group ID is the one specified in the process_group_id parameter.

       If the process_group_id parameter contains 0 (zero), the setpgid() function sets the process group ID of the specified  process	using  the
       process group ID of the calling process.  The specified process is the one identified by the process_id parameter.

       The setpgid() function supports job control.

       The setpgrp() function sets the process group ID of the calling process to be equal to the process ID of the calling process.  If the func-
       tion creates a new session, the new session has no controlling terminal.  This function does not change the process group ID of	a  session
       leader.

NOTES

       [Tru64  UNIX]  When compiled in the X/Open UNIX environment, calls to the setpgrp() function are internally renamed by prepending _E to the
       function name. When you are debugging a module that includes the setpgrp() function and for which _XOPEN_SOURCE_EXTENDED has been  defined,
       use _Esetpgrp to refer to the setpgrp() call.  See standards(5) for further information.

       [Tru64  UNIX]  The  backward-compatible	version of the setpgrp() function is  supported for use outside of the System V habitat or X/Open-
       UNIX environment.  This version of setpgrp( behaves like the setpgid() function.  In this case, you specify a process ID and process  group
       ID as parameters in the call to setpgrp().  The setpgrp() function does not change the process group ID of a session leader.

RETURN VALUES

       Upon  successful  completion,  the  setpgid()  function returns a value of 0 (zero). Otherwise, the function returns a value of -1 and sets
       errno to indicate the error.

       Upon successful completion, the setpgrp() function returns the new process group ID.

       [Tru64 UNIX]  The alternate version of setpgrp() returns a value of 0 (zero) on successful completion.  Otherwise, the function	returns  a
       value of -1 and sets errno to indicate the error.

ERRORS

       The  setpgid()  function sets errno to the specified values for the following conditions: The value of the process_id parameter matches the
       process ID of a child process of the calling process and the child process has successfully executed one  of  the  exec()  functions.   The
       value of the process_group_id parameter is less than or equal to 0 (zero), or is not a valid process ID.  The value of the process_group_id
       parameter is a valid process ID, but that process is not in the same session  as  the  calling  process.   The  process	indicated  by  the
       process_id parameter is a session leader.

	      The  value of the process_id parameter matches the process ID of a child process of the calling process and the child process is not
	      in the same session as the calling process.

	      The value of the process_group_id parameter is valid but does not match the process ID of the process indicated  by  the	process_id
	      parameter, and there is no process with a process group ID that matches the value of the process_group_id parameter in the same ses-
	      sion as the calling process.  The value of the process_id parameter does not match the process ID of the calling	process  or  of  a
	      child process of the calling process.

       No errors are defined for the standard version of the setpgrp() function.

       [Tru64 UNIX]  The backward-compatible version of setpgrp() sets errno to the same values as setpgid().

RELATED INFORMATION

       Functions: exec(2), fork(2), getpid(2), getsid(2), kill(2)

       Standards: standards(5)

       Guides:	Programmer's Guide delim off

																	setpgid(2)