Linux.com

__freading.3

STDIO_EXT

Section: Linux Programmer's Manual (3)
Updated: 2001-12-16
Index Return to Main Contents
 

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 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 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.  

SEE ALSO

flockfile(3), fpurge(3)  

COLOPHON

This page is part of release 3.21 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
SEE ALSO
COLOPHON

 

Comments

Subscribe to Comments Feed

Upcoming Linux Foundation Courses

  1. LFD320 Linux Kernel Internals and Debugging
    04 Aug » 08 Aug - Virtual
    Details
  2. LFD405 Embedded Linux Development with Yocto Project
    04 Aug » 07 Aug - Santa Clara, CA
    Details
  3. LFD312 Developing Applications For Linux
    18 Aug » 22 Aug - Virtual
    Details

View All Upcoming Courses

Become an Individual Member
Check out the Friday Funnies

Sign Up For the Linux.com Newsletter


Who we are ?

The Linux Foundation is a non-profit consortium dedicated to the growth of Linux.

More About the foundation...

Frequent Questions

Join / Linux Training / Board