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

  process_group_id
	    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 function 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:

  [EACCES]  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.

  [EINVAL]  The value of the process_group_id parameter is less than or equal
	    to 0 (zero), or is not a valid process ID.

  [EPERM]   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.

  [EPERM]   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
	    session as the calling process.

  [ESRCH]   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

Index for Section 2

Alphabetical listing for S

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