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explain_settimeofday(3)	   Library Functions Manual    explain_settimeofday(3)

NAME
       explain_settimeofday - explain settimeofday(2) errors

SYNOPSIS
       #include	<libexplain/settimeofday.h>
       const char *explain_settimeofday(const struct timeval *tv, const	struct
       timezone	*tz);
       const char *explain_errno_settimeofday(int errnum, const	struct timeval
       *tv, const struct timezone *tz);
       void explain_message_settimeofday(char *message,	int message_size,
       const struct timeval *tv, const struct timezone *tz);
       void explain_message_errno_settimeofday(char *message, int mes-
       sage_size, int errnum, const struct timeval *tv,	const struct timezone
       *tz);

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

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

       The explain_settimeofday	function is used to obtain an  explanation  of
       an  error  returned  by	the settimeofday(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.

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

       tz      The  original tz, exactly as passed to the settimeofday(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, 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 (settimeofday(tv, tz) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_settimeofday(tv, tz));
		  exit(EXIT_FAILURE);
	      }

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

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

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

       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 settimeofday(2)  sys-
	       tem call.

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

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

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

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

       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.

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

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

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

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

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

       The explain_message_errno_settimeofday function is used	to  obtain  an
       explanation  of	an  error returned by the settimeofday(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.

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

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

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

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

SEE ALSO
       settimeofday(2)
	       sets system time

       explain_settimeofday_or_die(3)
	       sets system time	and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2013 Peter	Miller

						       explain_settimeofday(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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