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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
       errnum, 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
       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.

       The errno global variable will be used to obtain the error value to  be
       decoded.

       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 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
       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
       explain_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
       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
       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.

       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 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
       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
       explain_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 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
               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
       explain_time_or_die(3) function.

   explain_message_errno_time
       void explain_message_errno_time(char *message, int message_size, int
       errnum, 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  better,  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
               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.

       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
       explain_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 0.19
       Copyright (C) 2009 Peter Miller

                                                               explain_time(3)