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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 er-
       ror 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  fol-
       lowing 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, in-
	       cluding other threads.

       Note: This function is not thread safe, because it shares a return buf-
       fer 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  fol-
       lowing 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, in-
	       cluding other threads.

       Note: This function is not thread safe, because it shares a return buf-
       fer 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 explana-
       tion 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  fol-
       lowing 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 re-
	       turned 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 ex-
       planation  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  fol-
       lowing 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 re-
	       turned 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 1.3
       Copyright (C) 2008 Peter	Miller

							    explain_readdir(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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