Provided by: libexplain-dev_1.4.D001-7_amd64 bug

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  message_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 following 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) system call.

       tz      The original tz, exactly as passed to the gettimeofday(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.

   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 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 following 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) system call.

       tz      The original tz, exactly as passed to the gettimeofday(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.

   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  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 following 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 returned message.

       tv      The original tv, exactly as passed to the gettimeofday(2) system call.

       tz      The original tz, exactly as passed to the gettimeofday(2) system call.

   explain_message_errno_gettimeofday
       void  explain_message_errno_gettimeofday(char  *message,  int  message_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 following 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 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.

       tv      The original tv, exactly as passed to the gettimeofday(2) system call.

       tz      The original tz, exactly as passed to the gettimeofday(2) system call.

SEE ALSO

       gettimeofday(2)
               get time

       explain_gettimeofday_or_die(3)
               get time and report errors

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2008 Peter Miller

                                                                          explain_gettimeofday(3)