_flushlbf

STDIO_EXT(3)		  Linux Programmer’s Manual		 STDIO_EXT(3)



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

SYNOPSIS
       #include <stdio.h>
       #include <stdio_ext.h>

       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 nonzero value if the stream  is	line-
       buffered, and zero otherwise.

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

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

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

       The  __fwriting()  function  returns  a nonzero 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  parame-
       ter 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
	      Don’t 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 stream’s buffer.

SEE ALSO
       flockfile(3), fpurge(3)



				  2001-12-16			 STDIO_EXT(3)