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explain_fclose(3)	   Library Functions Manual	     explain_fclose(3)

NAME
       explain_fclose -	explain	fclose(3) errors

SYNOPSIS
       #include	<libexplain/fclose.h>
       const char *explain_fclose(FILE *fp);
       const char *explain_errno_fclose(int errnum, FILE *fp);
       void explain_message_fclose(char	*message, int message_size, FILE *fp);
       void  explain_message_errno_fclose(char *message, int message_size, int
       errnum, FILE *fp);

DESCRIPTION
       These functions may be used to obtain explanations of fclose(3) errors.

   explain_fclose
       const char *explain_fclose(FILE * fp);

       The explain_fclose function is used to obtain an	explanation of an  er-
       ror  returned  by  the  fclose(3) function.  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 (fclose(fp))
	      {
		  fprintf(stderr, "%s\n", explain_fclose(fp));
		  exit(EXIT_FAILURE);
	      }

       fp      The  original  fp,  exactly  as	passed to the fclose(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.

       Note: This function may be of little diagnostic value, because libc may
       have destroyed any useful context, leaving nothing  for	libexplain  to
       work  with  (this  is true of glibc in particular).  For	files that are
       open for	writing, you will obtain  more	useful	information  by	 first
       calling fflush(3), as in	the following example
	      if (fflush(fp))
	      {
		  fprintf(stderr, "%s\n", explain_fflush(fp));
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  fprintf(stderr, "%s\n", explain_fclose(fp));
		  exit(EXIT_FAILURE);
	      }

   explain_errno_fclose
       const char *explain_errno_fclose(int errnum, FILE * fp);

       The  explain_errno_fclose  function is used to obtain an	explanation of
       an error	returned by the	fclose(3) function.   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 (fclose(fp))
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_fclose(err, 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.

       fp      The  original  fp,  exactly  as	passed to the fclose(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.

       Note: This function may be of little diagnostic value, because libc may
       have destroyed any useful context, leaving nothing  for	libexplain  to
       work  with  (this  is true of glibc in particular).  For	files that are
       open for	writing, you will obtain  more	useful	information  by	 first
       calling fflush(3), as in	the following example
	      if (fflush(fp))
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_fflush(err, fp));
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_fclose(err, fp));
		  exit(EXIT_FAILURE);
	      }

   explain_message_fclose
       void explain_message_fclose(char	*message, int message_size, FILE *fp);

       The explain_message_fclose function is used to obtain an	explanation of
       an error	returned by the	fclose(3) function.   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 (fclose(fp))
	      {
		  char message[3000];
		  explain_message_fclose(message, sizeof(message), fp);
		  fprintf(stderr, "%s\n", 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.

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

       Note: This function may be of little diagnostic value, because libc may
       have  destroyed	any  useful context, leaving nothing for libexplain to
       work with (this is true of glibc	in particular).	 For  files  that  are
       open  for  writing,  you	 will  obtain more useful information by first
       calling fflush(3), as in	the following example
	      if (fflush(fp))
	      {
		  char message[3000];
		  explain_message_fflush(message, sizeof(message), fp);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  char message[3000];
		  explain_message_fclose(message, sizeof(message), fp);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

   explain_message_errno_fclose
       void explain_message_errno_fclose(char *message,	int message_size,  int
       errnum, FILE *fp);

       The explain_message_errno_fclose	function is used to obtain an explana-
       tion of an error	returned by the	fclose(3)  function.   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 exameple:
	      if (fclose(fp))
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_fclose(message,	sizeof(message),
		      err, fp);
		  fprintf(stderr, "%s\n", 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.

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

       Note: This function may be of little diagnostic value, because libc may
       have destroyed any useful context, leaving nothing  for	libexplain  to
       work  with  (this  is true of glibc in particular).  For	files that are
       open for	writing, you will obtain  more	useful	information  by	 first
       calling fflush(3), as in	the following example
	      if (fflush(fp))
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_fflush(message,	sizeof(message),
		      err, fp);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_fclose(message,	sizeof(message),
		      err, fp);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

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

							     explain_fclose(3)

NAME | SYNOPSIS | DESCRIPTION | COPYRIGHT | AUTHOR

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