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explain_setgid(3)	   Library Functions Manual	     explain_setgid(3)

NAME
       explain_setgid -	explain	setgid(2) errors

SYNOPSIS
       #include	<libexplain/setgid.h>
       const char *explain_setgid(gid_t	gid);
       const char *explain_errno_setgid(int errnum, gid_t gid);
       void explain_message_setgid(char	*message, int message_size, gid_t
       gid);
       void explain_message_errno_setgid(char *message,	int message_size, int
       errnum, gid_t gid);

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

   explain_setgid
       const char *explain_setgid(gid_t	gid);

       The explain_setgid function is used to obtain an	explanation of an  er-
       ror  returned  by the setgid(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.

       gid     The original gid, exactly as passed  to	the  setgid(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 (setgid(gid) <	0)
	      {
		  fprintf(stderr, "%s\n", explain_setgid(gid));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_setgid
       const char *explain_errno_setgid(int errnum, gid_t gid);

       The explain_errno_setgid	function is used to obtain an  explanation  of
       an  error  returned by the setgid(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.

       gid     The  original  gid,  exactly  as	passed to the setgid(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 (setgid(gid) <	0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_setgid(err, gid));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_setgid
       void explain_message_setgid(char	*message, int message_size, gid_t
       gid);

       The explain_message_setgid function is used to obtain an	explanation of
       an  error  returned by the setgid(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.

       gid     The  original  gid,  exactly  as	passed to the setgid(2)	system
	       call.

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

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

   explain_message_errno_setgid
       void explain_message_errno_setgid(char *message,	int message_size, int
       errnum, gid_t gid);

       The explain_message_errno_setgid	function is used to obtain an explana-
       tion of an error	returned by the	setgid(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.

       gid     The  original  gid,  exactly  as	passed to the setgid(2)	system
	       call.

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

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

SEE ALSO
       setgid(2)
	       set group identity

       explain_setgid_or_die(3)
	       set group identity and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2012 Peter	Miller

							     explain_setgid(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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