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explain_fgetc(3)	   Library Functions Manual	      explain_fgetc(3)

NAME
       explain_fgetc - explain fgetc(3)	errors

SYNOPSIS
       #include	<libexplain/fgetc.h>
       const char *explain_fgetc(FILE *fp);
       const char *explain_errno_fgetc(int errnum, FILE	*fp);
       void explain_message_fgetc(char *message, int message_size, FILE	*fp);
       void  explain_message_errno_fgetc(char  *message, int message_size, int
       errnum, FILE *fp);

DESCRIPTION
       These functions may be used to obtain explanations for errors  returned
       by the fgetc(3) system call.

   explain_fgetc
       const char *explain_fgetc(FILE *fp);

       The explain_fgetc function is used to obtain an explanation of an error
       returned	by the fgetc(3)	system call.  The least	the message will  con-
       tain  is	the value of strerror(errno), but usually it will do much bet-
       ter, 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:
	      int c = fgetc(fp);
	      if (c == EOF && ferror(fp))
	      {
		  fprintf(stderr, "%s\n", explain_fgetc(fp));
		  exit(EXIT_FAILURE);
	      }

       fp      The original fp,	exactly	as passed to the fgetc(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_fgetc
       const char *explain_errno_fgetc(int errnum, FILE	*fp);

       The explain_errno_fgetc function	is used	to obtain an explanation of an
       error returned by the fgetc(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:
	      int c = fgetc(fp);
	      if (c == EOF && ferror(fp))
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_fgetc(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 fgetc(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_fgetc
       void explain_message_fgetc(char *message, int message_size, FILE	*fp);

       The explain_message_fgetc function may be used to  obtain  an  explana-
       tion  of	 an error returned by the fgetc(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:
	      int c = fgetc(fp);
	      if (c == EOF && ferror(fp))
	      {
		  char message[3000];
		  explain_message_fgetc(message, sizeof(message), fp);
		  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.

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

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

       The  explain_message_errno_fgetc	 function may be used to obtain	an ex-
       planation of an error returned by the fgetc(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:
	      int c = fgetc(fp);
	      if (c == EOF && ferror(fp))
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_fgetc(message, sizeof(message),	err, fp);
		  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.

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

SEE ALSO
       fgetc(3)
	       input of	characters

       explain_fgetc_or_die(3)
	       input of	characters and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

							      explain_fgetc(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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