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explain_setbuf(3)	   Library Functions Manual	     explain_setbuf(3)

NAME
       explain_setbuf -	explain	setbuf(3) errors

SYNOPSIS
       #include	<libexplain/setbuf.h>
       const char *explain_setbuf(FILE *fp, char *data);
       const char *explain_errno_setbuf(int errnum, FILE *fp, char *data);
       void explain_message_setbuf(char	*message, int message_size, FILE *fp,
       char *data);
       void explain_message_errno_setbuf(char *message,	int message_size, int
       errnum, FILE *fp, char *data);

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

   explain_setbuf
       const char *explain_setbuf(FILE *fp, char *data);

       The explain_setbuf function is used to obtain an	explanation of an  er-
       ror  returned  by the setbuf(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.

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

       data    The  original  data,  exactly as	passed to the setbuf(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 buf-
       fer across all threads, and many	other functions	in this	library.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      errno = 0;
	      void result = setbuf(fp, data);
	      if (result < 0 &&	errno != 0)
	      {
		  fprintf(stderr, "%s\n", explain_setbuf(fp, data));
		  exit(EXIT_FAILURE);
	      }

       The above code example is available pre-packaged	 as  the  explain_set-
       buf_or_die(3) function.

   explain_errno_setbuf
       const char *explain_errno_setbuf(int errnum, FILE *fp, char *data);

       The  explain_errno_setbuf  function is used to obtain an	explanation of
       an error	returned by the	setbuf(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.

       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  setbuf(3)	system
	       call.

       data    The  original  data,  exactly as	passed to the setbuf(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 buf-
       fer across all threads, and many	other functions	in this	library.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      errno = 0;
	      void result = setbuf(fp, data);
	      if (result < 0 &&	errno != 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_setbuf(err, fp,
		  data));
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example is available pre-packaged as the explain_set-
       buf_or_die(3) function.

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

       The explain_message_setbuf function is used to obtain an	explanation of
       an error	returned by the	setbuf(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.

       message The location in which to	store the returned message. If a suit-
	       able 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  setbuf(3)	system
	       call.

       data    The  original  data,  exactly as	passed to the setbuf(3)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      errno = 0;
	      void result = setbuf(fp, data);
	      if (result < 0 &&	errno != 0)
	      {
		  char message[3000];
		  explain_message_setbuf(message, sizeof(message), fp, data);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example is available pre-packaged as the explain_set-
       buf_or_die(3) function.

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

       The explain_message_errno_setbuf	function is used to obtain an explana-
       tion of an error	returned by the	setbuf(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.

       message The location in which to	store the returned message. If a suit-
	       able 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 setbuf(3)	system
	       call.

       data    The original data, exactly as passed to	the  setbuf(3)	system
	       call.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      errno = 0;
	      void result = setbuf(fp, data);
	      if (result < 0 &&	errno != 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_setbuf(message,	sizeof(message), err,
		  fp, data);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example is available pre-packaged as the explain_set-
       buf_or_die(3) function.

SEE ALSO
       setbuf(3)
	       set stream buffer

       explain_setbuf_or_die(3)
	       set stream buffer and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2010 Peter	Miller

							     explain_setbuf(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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