explain_setpgrp_or_die(3) [debian man page]

explain_setpgrp_or_die(3)				     Library Functions Manual					 explain_setpgrp_or_die(3)

NAME

       explain_setpgrp_or_die - set process group and report errors

SYNOPSIS

       #include <libexplain/setpgrp.h>
       void explain_setpgrp_or_die(pid_t pid, pid_t pgid);
       int explain_setpgrp_on_error(pid_t pid, pid_t pgid);

DESCRIPTION

       The  explain_setpgrp_or_die  function  is  used	to  call  the setpgrp(2) system call. On failure an explanation will be printed to stderr,
       obtained from the explain_setpgrp(3) function, and then the process terminates by calling exit(EXIT_FAILURE).

       The explain_setpgrp_on_error function is used to call the setpgrp(2) system call. On failure an explanation  will  be  printed  to  stderr,
       obtained from the explain_setpgrp(3) function, but still returns to the caller.

       pid     The pid, exactly as to be passed to the setpgrp(2) system call.

       pgid    The pgid, exactly as to be passed to the setpgrp(2) system call.

       Note:  the  setpgrp(2)  function  has two implementations.  The System V version has no arguments, while the BSD version has two arguments.
       For simplicity of implementation, the argument list seen here includes the pid and pgid arguments.

       The System V getpgid() semantics can be obtained by calling setpgrp(0, 0) on systems with the BSD version, and this is the API  for  libex-
       plain, even on systems that do not use the BSD API.

RETURN VALUE

       The  explain_setpgrp_or_die  function  only  returns on success, see setpgrp(2) for more information. On failure, prints an explanation and
       exits, it does not return.

       The explain_setpgrp_on_error function always returns the value return by the wrapped setpgrp(2) system call.

EXAMPLE

       The explain_setpgrp_or_die function is intended to be used in a fashion similar to the following example:
	      explain_setpgrp_or_die(pid, pgid);

SEE ALSO

       setpgrp(2)
	       set process group

       explain_setpgrp(3)
	       explain setpgrp(2) errors

       exit(2) terminate the calling process

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2011 Peter Miller

															 explain_setpgrp_or_die(3)

SETPGID(2)						      BSD System Calls Manual							SETPGID(2)

NAME

     setpgid, setpgrp -- set process group

SYNOPSIS

     #include <unistd.h>

     int
     setpgid(pid_t pid, pid_t pgid);

     pid_t
     setpgrp(void);

DESCRIPTION

     Setpgid() sets the process group of the specified process pid to the specified pgid.  If pid is zero, then the call applies to the current
     process.

     If the invoker is not the super-user, then the affected process must have the same effective user-id as the invoker or be a descendant of the
     invoking process.

     If the calling process is not already a session leader, setpgrp() sets the process group ID of the calling process to that of the calling
     process.  Any new session that this creates will have no controlling terminal.

RETURN VALUES

     Setpgid() returns 0 when the operation was successful.  If the request failed, -1 is returned and the global variable errno indicates the
     reason.

ERRORS

     Setpgid() will fail and the process group will not be altered if:

     [EACCES]		The value of the pid argument 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 pgid argument is less than 0 or is not a value supported by the implementation.

     [EPERM]		The process indicated by the pid argument is a session leader.

     [EPERM]		The effective user ID of the requested process is different from that of the caller and the process is not a descendant of
			the calling process.

     [EPERM]		The value of the pgid argument is valid, but does not match the process ID of the process indicated by the pid argument
			and there is no process with a process group ID that matches the value of the pgid argument in the same session as the
			calling process.

     [ESRCH]		The value of the pid argument does not match the process ID of the calling process or of a child process of the calling
			process.

LEGACY SYNOPSIS

     #include <unistd.h>

     int
     setpgrp(pid_t pid, pid_t pgid);

     The legacy setpgrp() function is a clone of the setpgid() function, retained for calling convention compatibility with historical versions of
     BSD.

COMPATIBILITY

     Use of the legacy version of the setpgrp() call will cause compiler diagnostics.  Use setpgid() instead.

     Use of private (and conflicting) prototypes for setpgrp() will cause compiler diagnostics.  Delete the private prototypes and include
     <unistd.h>.

SEE ALSO

     getpgrp(2), compat(5)

STANDARDS

     The setpgid() function conforms to IEEE Std 1003.1-1988 (``POSIX.1'').

4th Berkeley Distribution					   June 4, 1993 					 4th Berkeley Distribution