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 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 following example:
	      if (fclose(fp))
	      {
		  fprintf(stderr, "%s
", 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, 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.

       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
", explain_fflush(fp));
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  fprintf(stderr, "%s
", 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 following example:
	      if (fclose(fp))
	      {
		  int err = errno;
		  fprintf(stderr, "%s
", 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 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.

       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,  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.

       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
", explain_errno_fflush(err, fp));
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  int err = errno;
		  fprintf(stderr, "%s
", 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 following example:
	      if (fclose(fp))
	      {
		  char message[3000];
		  explain_message_fclose(message, sizeof(message), fp);
		  fprintf(stderr, "%s
", 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 returned 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
", message);
		  exit(EXIT_FAILURE);
	      }
	      if (fclose(fp))
	      {
		  char message[3000];
		  explain_message_fclose(message, sizeof(message), fp);
		  fprintf(stderr, "%s
", 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 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 following exameple:
	      if (fclose(fp))
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_fclose(message, sizeof(message),
		      err, fp);
		  fprintf(stderr, "%s
", 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 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.

       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
", 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
", message);
		  exit(EXIT_FAILURE);
	      }

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2008 Peter Miller

AUTHOR

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

																 explain_fclose(3)