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explain_gettimeofday(3)	   Library Functions Manual    explain_gettimeofday(3)

NAME
       explain_gettimeofday - explain gettimeofday(2) errors

SYNOPSIS
       #include	<libexplain/gettimeofday.h>
       const  char  *explain_gettimeofday(struct  timeval *tv, struct timezone
       *tz);
       const char *explain_errno_gettimeofday(int errnum, struct timeval  *tv,
       struct timezone *tz);
       void   explain_message_gettimeofday(char	 *message,  int	 message_size,
       struct timeval *tv, struct timezone *tz);
       void   explain_message_errno_gettimeofday(char	*message,   int	  mes-
       sage_size, int errnum, struct timeval *tv, struct timezone *tz);

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

   explain_gettimeofday
       const char *explain_gettimeofday(struct timeval	*tv,  struct  timezone
       *tz);

       The  explain_gettimeofday  function is used to obtain an	explanation of
       an error	returned by the	gettimeofday(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.

       This  function  is intended to be used in a fashion similar to the fol-
       lowing example:
	      if (gettimeofday(tv, tz) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_gettimeofday(tv, tz));
		  exit(EXIT_FAILURE);
	      }

       tv      The original tv,	exactly	as passed to the gettimeofday(2)  sys-
	       tem call.

       tz      The  original tz, exactly as passed to the gettimeofday(2) sys-
	       tem 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, in-
	       cluding 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.

   explain_errno_gettimeofday
       const  char *explain_errno_gettimeofday(int errnum, struct timeval *tv,
       struct timezone *tz);

       The explain_errno_gettimeofday function is used to obtain  an  explana-
       tion  of	 an  error  returned  by the gettimeofday(2) system call.  The
       least the message will contain is the value  of	strerror(errnum),  but
       usually	it  will  do much better, and indicate the underlying cause in
       more detail.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (gettimeofday(tv, tz) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_gettimeofday(err, tv, tz));
		  exit(EXIT_FAILURE);
	      }

       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.

       tv      The  original tv, exactly as passed to the gettimeofday(2) sys-
	       tem call.

       tz      The original tz,	exactly	as passed to the gettimeofday(2)  sys-
	       tem 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,  in-
	       cluding 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.

   explain_message_gettimeofday
       void  explain_message_gettimeofday(char	*message,  int	 message_size,
       struct timeval *tv, struct timezone *tz);

       The explain_message_gettimeofday	function may be	used to	 obtain	an ex-
       planation of an error returned by the gettimeofday(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.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (gettimeofday(tv, tz) < 0)
	      {
		  char message[3000];
		  explain_message_gettimeofday(message,	sizeof(message), tv, tz);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       message The  location  in  which	 to  store the returned	message.  If a
	       suitable	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.

       tv      The original tv,	exactly	as passed to the gettimeofday(2)  sys-
	       tem call.

       tz      The  original tz, exactly as passed to the gettimeofday(2) sys-
	       tem call.

   explain_message_errno_gettimeofday
       void   explain_message_errno_gettimeofday(char	*message,   int	  mes-
       sage_size, int errnum, struct timeval *tv, struct timezone *tz);

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

       This  function  is intended to be used in a fashion similar to the fol-
       lowing example:
	      if (gettimeofday(tv, tz) < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_gettimeofday(message, sizeof(message), err,
		      tv, tz);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store  the  returned  message.	 If  a
	       suitable	 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.

       tv      The  original tv, exactly as passed to the gettimeofday(2) sys-
	       tem call.

       tz      The original tz,	exactly	as passed to the gettimeofday(2)  sys-
	       tem call.

SEE ALSO
       gettimeofday(2)
	       get time

       explain_gettimeofday_or_die(3)
	       get time	and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

						       explain_gettimeofday(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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