explain_readdir(3)					     Library Functions Manual						explain_readdir(3)

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
", 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 mes-
       sage 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
", 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 neces-
	       sary 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
", 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
", 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 neces-
	       sary 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 0.52
       Copyright (C) 2008 Peter Miller

																explain_readdir(3)