STDIO_EXT
STDIO_EXT
NAMESYNOPSIS
DESCRIPTION
ATTRIBUTES
SEE ALSO
COLOPHON
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 operation, 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 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 flockfile(3) in case there is more than one thread), and the stdio routines will not do locking until the state is reset to FSETLOCKING_INTERNAL.
FSETLOCKING_QUERY
Don’t change the type of locking. (Only return it.)
The _flushlbf() function flushes all line-buffered streams. (Presumably 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.
ATTRIBUTES
Multithreading
(see pthreads(7))
The __fbufsize(), __fpending(),
__fpurge() and __fsetlocking() functions do
not lock the stream, so they are not thread-safe.
The __flbf(), __freadable(), __freading(), __fwritable(), __fwriting() and _flushlbf() functions are thread-safe.
SEE ALSO
COLOPHON
This page is part of release 3.69 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man−pages/.
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