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explain_getpgid(3)	   Library Functions Manual	    explain_getpgid(3)

NAME
       explain_getpgid - explain getpgid(2) errors

SYNOPSIS
       #include	<libexplain/getpgid.h>
       const char *explain_getpgid(pid_t pid);
       const char *explain_errno_getpgid(int errnum, pid_t pid);
       void explain_message_getpgid(char *message, int message_size, pid_t
       pid);
       void explain_message_errno_getpgid(char *message, int message_size, int
       errnum, pid_t pid);

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

   explain_getpgid
       const char *explain_getpgid(pid_t pid);

       The explain_getpgid function is used to obtain an explanation of	an er-
       ror  returned by	the getpgid(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  getpgid(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:
	      pid_t result = getpgid(pid);
	      if (result < 0)
	      {
		  fprintf(stderr, "%s\n", explain_getpgid(pid));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_getpgid
       const char *explain_errno_getpgid(int errnum, pid_t pid);

       The explain_errno_getpgid function is used to obtain an explanation  of
       an  error returned by the getpgid(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 getpgid(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:
	      pid_t result = getpgid(pid);
	      if (result < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_getpgid(err, pid));
		  exit(EXIT_FAILURE);
	      }

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

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

       The explain_message_getpgid function is used to obtain  an  explanation
       of  an error returned by	the getpgid(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 getpgid(2)	system
	       call.

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

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

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

       The  explain_message_errno_getpgid function is used to obtain an	expla-
       nation of an error returned by the getpgid(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  getpgid(2)	system
	       call.

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

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

SEE ALSO
       getpgid(2)
	       get process group

       explain_getpgid_or_die(3)
	       get process group and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2011 Peter	Miller

							    explain_getpgid(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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