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explain_freopen(3)	   Library Functions Manual	    explain_freopen(3)

NAME
       explain_freopen - explain freopen(3) errors

SYNOPSIS
       #include	<libexplain/freopen.h>
       const  char  *explain_freopen(const  char *pathname, const char *flags,
       FILE *fp);
       const char *explain_errno_freopen(int  errnum,  const  char  *pathname,
       const char *flags, FILE *fp);
       void  explain_message_freopen(char  *message,  int  message_size, const
       char *pathname, const char *flags, FILE *fp);
       void explain_message_errno_freopen(char *message, int message_size, int
       errnum, const char *pathname, const char	*flags,	FILE *fp);

DESCRIPTION
       These  functions	 may be	used to	obtain explanations for	freopen(3) er-
       rors.

   explain_freopen
       const char *explain_freopen(const char *pathname,  const	 char  *flags,
       FILE *fp);

       The explain_freopen function is used to obtain an explanation of	an er-
       ror returned by the freopen(3) 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:
	      if (!freopen(pathname, flags, fp))
	      {
		  fprintf(stderr, '%s0,	explain_freopen(pathname, flags, fp));
		  exit(EXIT_FAILURE);
	      }

       pathname
	       The original pathname, exactly as passed	to the freopen(3) sys-
	       tem call.

       flags   The  original flags, exactly as passed to the freopen(3)	system
	       call.

       fp      The original fp,	exactly	as passed  to  the  freopen(3)	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_freopen
       const char *explain_errno_freopen(int  errnum,  const  char  *pathname,
       const char *flags, FILE *fp);

       The  explain_errno_freopen function is used to obtain an	explanation of
       an error	returned by the	freopen(3) 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:
	      if (freopen(pathname, flags, fp))
	      {
		  int err = errno;
		  fprintf(stderr, '%s0,	explain_errno_freopen(err, pathname,
		      flags, fp));
		  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.

       pathname
	       The original pathname, exactly as passed	to the freopen(3) sys-
	       tem call.

       flags   The original flags, exactly as passed to	the freopen(3)	system
	       call.

       fp      The  original  fp,  exactly  as passed to the freopen(3)	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_freopen
       void  explain_message_freopen(char  *message,  int  message_size, const
       char *pathname, const char *flags, FILE *fp);

       The explain_message_freopen function is used to obtain  an  explanation
       of an error returned by the freopen(3) system call.  The	least the mes-
       sage 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:
	      if (!freopen(pathname, flags, fp))
	      {
		  char message[3000];
		  explain_message_freopen(message, sizeof(message), pathname, flags,
		      fp);
		  fprintf(stderr, '%s0,	message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store the returned message.  Because a
	       message return buffer  has  been	 supplied,  this  function  is
	       thread safe.

       message_size
	       The  size  in  bytes  of	the location in	which to store the re-
	       turned message.

       pathname
	       The original pathname, exactly as passed	to the freopen(3) sys-
	       tem call.

       flags   The  original flags, exactly as passed to the freopen(3)	system
	       call.

       fp      The original fp,	exactly	as passed  to  the  freopen(3)	system
	       call.

   explain_message_errno_freopen
       void explain_message_errno_freopen(char *message, int message_size, int
       errnum, const char *pathname, const char	*flags,	FILE *fp);

       The explain_message_errno_freopen function is used to obtain an	expla-
       nation  of  an error returned by	the freopen(3) 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 de-
       tail.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (!freopen(pathname, flags, fp))
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_freopen(message, sizeof(message), err,
		      pathname,	flags, fp);
		  fprintf(stderr, '%s0,	message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store the returned message.  Because a
	       message return buffer  has  been	 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.

       pathname
	       The original pathname, exactly as passed	to the freopen(3) sys-
	       tem call.

       flags   The  original flags, exactly as passed to the freopen(3)	system
	       call.

       fp      The original fp,	exactly	as passed  to  the  freopen(3)	system
	       call.

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

AUTHOR
       Written by Peter	Miller <pmiller@opensource.org.au>

							    explain_freopen(3)

NAME | SYNOPSIS | DESCRIPTION | COPYRIGHT | AUTHOR

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