NAME

       explain_readdir - explain readdir(2) errors

SYNOPSIS

       #include <libexplain/readdir.h>
       const char *explain_readdir(DIR *dir);
       const char *explain_errno_readdir(int errnum, DIR *dir);
       void explain_message_readdir(char *message, int message_size, DIR *dir);
       void explain_message_errno_readdir(char *message, int message_size, int errnum, DIR *dir);

DESCRIPTION

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

   explain_readdir
       const char *explain_readdir(DIR *dir);

       The  explain_readdir  function  is  used  to obtain an explanation of an error returned by the readdir(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:
              errno = 0;
              struct dirent *dep = readdir(dir);
              if (!dep && errno != 0)
              {
                  fprintf(stderr, "%s\n", explain_readdir(dir));
                  exit(EXIT_FAILURE);
              }

       dir     The original dir, exactly as passed to the readdir(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_readdir
       const char *explain_errno_readdir(int errnum, DIR *dir);

       The explain_errno_readdir function is used  to  obtain  an  explanation  of  an  error  returned  by  the
       readdir(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:
              errno = 0;
              struct dirent *dep = readdir(dir);
              int err = errno;
              if (!dep && errno != 0)
              {
                  fprintf(stderr, "%s\n", explain_errno_readdir(err, dir));
                  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.

       dir     The original dir, exactly as passed to the readdir(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_readdir
       void explain_message_readdir(char *message, int message_size, DIR *dir);

       The  explain_message_readdir  function  may be used to  obtain an explanation of an error returned by the
       readdir(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:
              errno = 0;
              struct dirent *dep = readdir(dir);
              if (!dep && errno != 0)
              {
                  char message[3000];
                  explain_message_readdir(message, sizeof(message), dir);
                  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.

       dir     The original dir, exactly as passed to the readdir(2) system call.

   explain_message_errno_readdir
       void explain_message_errno_readdir(char *message, int message_size, int errnum, DIR *dir);

       The explain_message_errno_readdir function may be used to obtain an explanation of an error  returned  by
       the  readdir(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:
              errno = 0;
              struct dirent *dep = readdir(dir);
              int err = errno;
              if (!dep && errno != 0)
              {
                  char message[3000];
                  explain_message_errno_readdir(message, sizeof(message), err, dir);
                  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.

       dir     The original dir, exactly as passed to the readdir(2) system call.

SEE ALSO

       readdir(2)
               read directory entry

       explain_readdir_or_die(3)
               read directory entry and report errors

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2008 Peter Miller

                                                                                              explain_readdir(3)