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explain_getresgid(3)	   Library Functions Manual	  explain_getresgid(3)

NAME
       explain_getresgid - explain getresgid(2)	errors

SYNOPSIS
       #include	<libexplain/getresgid.h>
       const char *explain_getresgid(gid_t *rgid, gid_t	*egid, gid_t *sgid);
       const char *explain_errno_getresgid(int errnum, gid_t *rgid, gid_t
       *egid, gid_t *sgid);
       void explain_message_getresgid(char *message, int message_size, gid_t
       *rgid, gid_t *egid, gid_t *sgid);
       void explain_message_errno_getresgid(char *message, int message_size,
       int errnum, gid_t *rgid,	gid_t *egid, gid_t *sgid);

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

   explain_getresgid
       const char *explain_getresgid(gid_t *rgid, gid_t	*egid, gid_t *sgid);

       The  explain_getresgid  function	is used	to obtain an explanation of an
       error returned by the getresgid(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.

       rgid    The original rgid, exactly as passed to the getresgid(2)	system
	       call.

       egid    The original egid, exactly as passed to the getresgid(2)	system
	       call.

       sgid    The original sgid, exactly as passed to the getresgid(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 (getresgid(rgid, egid,	sgid) <	0)
	      {
		  fprintf(stderr, "%s\n", explain_getresgid(rgid, egid,
		  sgid));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_getresgid
       const char *explain_errno_getresgid(int errnum, gid_t *rgid, gid_t
       *egid, gid_t *sgid);

       The  explain_errno_getresgid  function is used to obtain	an explanation
       of an error returned by the getresgid(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.

       rgid    The original rgid, exactly as passed to the getresgid(2)	system
	       call.

       egid    The original egid, exactly as passed to the getresgid(2)	system
	       call.

       sgid    The original sgid, exactly as passed to the getresgid(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 (getresgid(rgid, egid,	sgid) <	0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_getresgid(err, rgid,
		  egid,	sgid));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_getresgid
       void explain_message_getresgid(char *message, int message_size, gid_t
       *rgid, gid_t *egid, gid_t *sgid);

       The explain_message_getresgid function is used to obtain	an explanation
       of  an  error  returned by the getresgid(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.

       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.

       rgid    The original rgid, exactly as passed to the getresgid(2)	system
	       call.

       egid    The original egid, exactly as passed to the getresgid(2)	system
	       call.

       sgid    The original sgid, exactly as passed to the getresgid(2)	system
	       call.

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

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

   explain_message_errno_getresgid
       void explain_message_errno_getresgid(char *message, int message_size,
       int errnum, gid_t *rgid,	gid_t *egid, gid_t *sgid);

       The explain_message_errno_getresgid function is used to obtain  an  ex-
       planation  of  an  error	returned by the	getresgid(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.

       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.

       rgid    The original rgid, exactly as passed to the getresgid(2)	system
	       call.

       egid    The original egid, exactly as passed to the getresgid(2)	system
	       call.

       sgid    The original sgid, exactly as passed to the getresgid(2)	system
	       call.

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

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

SEE ALSO
       getresgid(2)
	       get real, effective and saved group IDs

       explain_getresgid_or_die(3)
	       get real, effective and saved group IDs and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2012 Peter	Miller

							  explain_getresgid(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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