stdio_ext
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
__fbufsize, __flbf, __fpending, __fpurge, __freadable,
__freading, __fsetlocking, __fwritable, __fwriting, _flushlbf -
interfaces to stdio FILE structure
LIBRARY
Standard C library
(
libc,~
-lc)
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 characters in the output buffer.
For wid-oriented streams the unit is wide characters.
This function is undefined on buffers in reading mode,
or opened rea-only.
The
__flbf()
function returns a nonzero value if the stream is lin-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 rea-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 writ-only (or
appen-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 lin-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
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
__fbufsize(),
__fpending(),
__fpurge(),
__fsetlocking()
| Thread safety | M-Safe race:stream
|
|
__flbf(),
__freadable(),
__freading(),
__fwritable(),
__fwriting(),
_flushlbf()
| Thread safety | M-Safe
|
SEE ALSO
flockfile(3),
fpurge(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- ATTRIBUTES
-
- SEE ALSO
-
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