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 libexplain, 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