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explain_time(3) 	    Library Functions Manual		 explain_time(3)

NAME
     explain_time - explain time(2) errors

SYNOPSIS
     #include <libexplain/time.h>
     const char *explain_time(time_t *t);
     const char *explain_errno_time(int errnum, time_t *t);
     void explain_message_time(char *message, int message_size, time_t *t);
     void explain_message_errno_time(char *message, int message_size, int er-
     rnum, time_t *t);

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

   explain_time
     const char *explain_time(time_t *t);

     The explain_time function is used to obtain an explanation of an error  re-
     turned  by  the  time(2) system call. The least the message will contain is
     the value of strerror(errno), but usually it will do much better, and indi-
     cate the underlying cause in more detail.

     The errno global variable will be used to obtain the error value to be  de-
     coded.

     t	     The original t, exactly as passed to the time(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  ar-
	     gument list.  This will be overwritten by the next call to any lib-
	     explain function which shares this buffer, including other threads.

     Note:  This  function is not thread safe, because it shares a return buffer
     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:
	    time_t result = time(t);
	    if (result == (time_t)-1)
	    {
		fprintf(stderr, "%s\n", explain_time(t));
		exit(EXIT_FAILURE);
	    }

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

   explain_errno_time
     const char *explain_errno_time(int errnum, time_t *t);

     The explain_errno_time function is used to obtain an explanation of an  er-
     ror returned by the time(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 neces-
	     sary if you need to call any code between the system call to be ex-
	     plained  and  this function, because many libc functions will alter
	     the value of errno.

     t	     The original t, exactly as passed to the time(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 ar-
	     gument list.  This will be overwritten by the next call to any lib-
	     explain function which shares this buffer, including other threads.

     Note: This function is not thread safe, because it shares a  return  buffer
     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:
	    time_t result = time(t);
	    if (result == (time_t)-1)
	    {
		int err = errno;
		fprintf(stderr, "%s\n", explain_errno_time(err, t));
		exit(EXIT_FAILURE);
	    }

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

   explain_message_time
     void explain_message_time(char *message, int message_size, time_t *t);

     The  explain_message_time	function  is used to obtain an explanation of an
     error returned by the time(2) system call. The least the message will  con-
     tain  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  de-
     coded.

     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	returned
	     message.

     t	     The original t, exactly as passed to the time(2) system call.

     Example:  This  function is intended to be used in a fashion similar to the
     following example:
	    time_t result = time(t);
	    if (result == (time_t)-1)
	    {
		char message[3000];
		explain_message_time(message, sizeof(message), t);
		fprintf(stderr, "%s\n", message);
		exit(EXIT_FAILURE);
	    }

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

   explain_message_errno_time
     void explain_message_errno_time(char *message, int message_size, int er-
     rnum, time_t *t);

     The explain_message_errno_time function is used to obtain an explanation of
     an  error	returned  by the time(2) system call. The least the message will
     contain is the value of strerror(errno), but usually it will do  much  bet-
     ter, and indicate the underlying cause in more detail.

     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	returned
	     message.

     errnum  The  error  value	to  be	decoded, usually obtained from the errno
	     global variable just before this function is called. This is neces-
	     sary if you need to call any code between the system call to be ex-
	     plained and this function, because many libc functions  will  alter
	     the value of errno.

     t	     The original t, exactly as passed to the time(2) system call.

     Example:  This  function is intended to be used in a fashion similar to the
     following example:
	    time_t result = time(t);
	    if (result == (time_t)-1)
	    {
		int err = errno;
		char message[3000];
		explain_message_errno_time(message, sizeof(message), err, t);
		fprintf(stderr, "%s\n", message);
		exit(EXIT_FAILURE);
	    }

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

SEE ALSO
     time(2)
	     get time in seconds

     explain_time_or_die(3)
	     get time in seconds and report errors

COPYRIGHT
     libexplain version 1.3
     Copyright (C) 2009 Peter Miller

								 explain_time(3)

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