STDIO_EXT(3)		   Linux Programmers Manual		 STDIO_EXT(3)



NAME
       __fbufsize,  __flbf,  __fpending,  __fpurge,  __freadable,  __freading,
       __fsetlocking, __fwritable, __fwriting, _flushlbf - interfaces to stdio
       FILE structure

SYNOPSIS
       #include 
       #include 

       size_t __fbufsize(FILE *stream);
       size_t __fpending(FILE *stream);
       int __flbf(FILE *stream);
       int __freadable(FILE *stream);
       int __fwritable(FILE *stream);
       int __freading(FILE *stream);
       int __fwriting(FILE *stream);
       int __fsetlocking(FILE *stream, int type);
       void _flushlbf(void);
       void __fpurge(FILE *stream);

DESCRIPTION
       Solaris	introduced  routines to allow portable access to the internals
       of the FILE structure, and glibc also implemented these.

       The __fbufsize() function returns the size of the buffer currently used
       by the given stream.

       The  __fpending()  function  returns  the number of bytes in the output
       buffer.	For wide-oriented streams the unit is wide  characters.   This
       function  is undefined on buffers in reading mode, or opened read-only.

       The __flbf() function returns a non-zero value if the stream  is  line-
       buffered, and zero otherwise.

       The  __freadable()  function  returns  a  non-zero  value if the stream
       allows reading, and zero otherwise.

       The __fwritable() function returns  a  non-zero	value  if  the	stream
       allows writing, and zero otherwise.

       The  __freading()  function  returns  a non-zero value if the stream is
       read-only, or if the last operation on the stream was a read operation,
       and zero otherwise.

       The  __fwriting()  function  returns  a non-zero value if the stream is
       write-only (or append-only), or if the last operation on the stream was
       a write operation, and zero otherwise.

       The  __fsetlocking() function can be used to select the desired type of
       locking on the stream.  It returns the current type.  The type argument
       can take the following three values:

       FSETLOCKING_INTERNAL
	      Perform  implicit  locking  around  every operation on the given
	      stream (except for the *_unlocked ones).	This is the default.

       FSETLOCKING_BYCALLER
	      The caller will take care of the locking (possibly using	flock
	      file(3)  in  case  there is more than one thread), and the stdio
	      routines will not do locking until the state is reset  to  FSET
	      LOCKING_INTERNAL.

       FSETLOCKING_QUERY
	      Dont change the type of locking.	(Only return it.)

       The  _flushlbf()  function flushes all line-buffered streams.  (Presum
       ably so that output to a terminal is forced  out,  say  before  reading
       keyboard input.)

       The __fpurge() function discards the contents of the streams buffer.

SEE ALSO
       flockfile(3), fpurge(3)

COLOPHON
       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



				  2001-12-16			  STDIO_EXT(3)