Provided by: libexplain-dev_1.4.D001-8_amd64 bug

NAME

       explain_adjtime - explain adjtime(2) errors

SYNOPSIS

       #include <libexplain/adjtime.h>
       const char *explain_adjtime(const struct timeval *delta, struct timeval *olddelta);
       const char *explain_errno_adjtime(int errnum, const struct timeval *delta, struct timeval
       *olddelta);
       void explain_message_adjtime(char *message, int message_size, const struct timeval *delta,
       struct timeval *olddelta);
       void explain_message_errno_adjtime(char *message, int message_size, int errnum, const
       struct timeval *delta, struct timeval *olddelta);

DESCRIPTION

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

   explain_adjtime
       const char *explain_adjtime(const struct timeval *delta, struct timeval *olddelta);

       The  explain_adjtime function is used to obtain an explanation of an error returned by the
       adjtime(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.

       delta   The original delta, exactly as passed to the adjtime(2) system call.

       olddelta
               The original olddelta, exactly as passed to the adjtime(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:
              if (adjtime(delta, olddelta) < 0)
              {
                  fprintf(stderr, "%s\n", explain_adjtime(delta, olddelta));
                  exit(EXIT_FAILURE);
              }

       The  above  code  example  is  available  pre‐packaged  as  the  explain_adjtime_or_die(3)
       function.

   explain_errno_adjtime
       const char *explain_errno_adjtime(int errnum, const struct timeval *delta, struct timeval
       *olddelta);

       The  explain_errno_adjtime  function is used to obtain an explanation of an error returned
       by the adjtime(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.

       delta   The original delta, exactly as passed to the adjtime(2) system call.

       olddelta
               The original olddelta, exactly as passed to the adjtime(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:
              if (adjtime(delta, olddelta) < 0)
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_adjtime(err, delta, olddelta));
                  exit(EXIT_FAILURE);
              }

       The  above  code  example  is  available  pre‐packaged  as  the  explain_adjtime_or_die(3)
       function.

   explain_message_adjtime
       void explain_message_adjtime(char *message, int message_size, const struct timeval *delta,
       struct timeval *olddelta);

       The explain_message_adjtime function is used to obtain an explanation of an error returned
       by  the  adjtime(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.

       delta   The original delta, exactly as passed to the adjtime(2) system call.

       olddelta
               The original olddelta, exactly as passed to the adjtime(2) system call.

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

       The  above  code  example  is  available  pre‐packaged  as  the  explain_adjtime_or_die(3)
       function.

   explain_message_errno_adjtime
       void explain_message_errno_adjtime(char *message, int message_size, int errnum, const
       struct timeval *delta, struct timeval *olddelta);

       The  explain_message_errno_adjtime  function  is used to obtain an explanation of an error
       returned by the adjtime(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.

       delta   The original delta, exactly as passed to the adjtime(2) system call.

       olddelta
               The original olddelta, exactly as passed to the adjtime(2) system call.

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

       The  above  code  example  is  available  pre‐packaged  as  the  explain_adjtime_or_die(3)
       function.

SEE ALSO

       adjtime(2)
               smoothly tune kernel clock

       explain_adjtime_or_die(3)
               smoothly tune kernel clock and report errors

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2009 Peter Miller

                                                                               explain_adjtime(3)