Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
explain_setpgid(3)	   Library Functions Manual	    explain_setpgid(3)

NAME
       explain_setpgid - explain setpgid(2) errors

SYNOPSIS
       #include	<libexplain/setpgid.h>
       const char *explain_setpgid(pid_t pid, pid_t pgid);
       const char *explain_errno_setpgid(int errnum, pid_t pid,	pid_t pgid);
       void explain_message_setpgid(char *message, int message_size, pid_t
       pid, pid_t pgid);
       void explain_message_errno_setpgid(char *message, int message_size, int
       errnum, pid_t pid, pid_t	pgid);

DESCRIPTION
       These  functions	may be used to obtain explanations for errors returned
       by the setpgid(2) system	call.

   explain_setpgid
       const char *explain_setpgid(pid_t pid, pid_t pgid);

       The explain_setpgid function is used to obtain an explanation of	an er-
       ror  returned by	the setpgid(2) system call. The	least the message will
       contain is the value of strerror(errno),	but usually it	will  do  much
       better, and indicate the	underlying cause in more detail.

       The  errno global variable will be used to obtain the error value to be
       decoded.

       pid     The original pid, exactly as passed to  the  setpgid(2)	system
	       call.

       pgid    The  original  pgid, exactly as passed to the setpgid(2)	system
	       call.

       Returns:
	       The message explaining the error. This message buffer is	shared
	       by  all	libexplain  functions  which do	not supply a buffer in
	       their argument list.  This will be overwritten by the next call
	       to  any libexplain function which shares	this buffer, including
	       other threads.

       Note: This function is not thread safe, because it shares a return buf-
       fer across all threads, and many	other functions	in this	library.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      if (setpgid(pid, pgid) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_setpgid(pid, pgid));
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is  available	 pre-packaged	as   the   ex-
       plain_setpgid_or_die(3) function.

   explain_errno_setpgid
       const char *explain_errno_setpgid(int errnum, pid_t pid,	pid_t pgid);

       The  explain_errno_setpgid function is used to obtain an	explanation of
       an error	returned by the	setpgid(2) system call.	The least the  message
       will  contain  is  the value of strerror(errno),	but usually it will do
       much better, and	indicate the underlying	cause in more detail.

       errnum  The error value to be decoded, usually obtained from the	 errno
	       global  variable	 just  before this function is called. This is
	       necessary if you	need to	call any code between the system  call
	       to  be explained	and this function, because many	libc functions
	       will alter the value of errno.

       pid     The original pid, exactly as passed to  the  setpgid(2)	system
	       call.

       pgid    The  original  pgid, exactly as passed to the setpgid(2)	system
	       call.

       Returns:
	       The message explaining the error. This message buffer is	shared
	       by  all	libexplain  functions  which do	not supply a buffer in
	       their argument list.  This will be overwritten by the next call
	       to  any libexplain function which shares	this buffer, including
	       other threads.

       Note: This function is not thread safe, because it shares a return buf-
       fer across all threads, and many	other functions	in this	library.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      if (setpgid(pid, pgid) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_setpgid(err, pid,
		  pgid));
		  exit(EXIT_FAILURE);
	      }

       The   above   code   example  is	 available  pre-packaged  as  the  ex-
       plain_setpgid_or_die(3) function.

   explain_message_setpgid
       void explain_message_setpgid(char *message, int message_size, pid_t
       pid, pid_t pgid);

       The  explain_message_setpgid  function is used to obtain	an explanation
       of an error returned by the setpgid(2) system call. The least the  mes-
       sage  will contain is the value of strerror(errno), but usually it will
       do much better, and indicate the	underlying cause in more detail.

       The errno global	variable will be used to obtain	the error value	to  be
       decoded.

       message The location in which to	store the returned message. If a suit-
	       able message return buffer is supplied, this function is	thread
	       safe.

       message_size
	       The  size  in  bytes  of	the location in	which to store the re-
	       turned message.

       pid     The original pid, exactly as passed to  the  setpgid(2)	system
	       call.

       pgid    The  original  pgid, exactly as passed to the setpgid(2)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (setpgid(pid, pgid) < 0)
	      {
		  char message[3000];
		  explain_message_setpgid(message, sizeof(message), pid,
		  pgid);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is  available	 pre-packaged	as   the   ex-
       plain_setpgid_or_die(3) function.

   explain_message_errno_setpgid
       void explain_message_errno_setpgid(char *message, int message_size, int
       errnum, pid_t pid, pid_t	pgid);

       The explain_message_errno_setpgid function is used to obtain an	expla-
       nation  of  an  error returned by the setpgid(2)	system call. The least
       the message will	contain	is the value of	strerror(errno),  but  usually
       it  will	 do much better, and indicate the underlying cause in more de-
       tail.

       message The location in which to	store the returned message. If a suit-
	       able message return buffer is supplied, this function is	thread
	       safe.

       message_size
	       The size	in bytes of the	location in which  to  store  the  re-
	       turned message.

       errnum  The  error value	to be decoded, usually obtained	from the errno
	       global variable just before this	function is  called.  This  is
	       necessary  if you need to call any code between the system call
	       to be explained and this	function, because many libc  functions
	       will alter the value of errno.

       pid     The  original  pid,  exactly as passed to the setpgid(2)	system
	       call.

       pgid    The original pgid, exactly as passed to the  setpgid(2)	system
	       call.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      if (setpgid(pid, pgid) < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_setpgid(message, sizeof(message), err,
		  pid, pgid);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The   above   code   example  is	 available  pre-packaged  as  the  ex-
       plain_setpgid_or_die(3) function.

SEE ALSO
       setpgid(2)
	       set process group

       explain_setpgid_or_die(3)
	       set process group and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2011 Peter	Miller

							    explain_setpgid(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=explain_setpgid&sektion=3&manpath=FreeBSD+12.2-RELEASE+and+Ports>

home | help