FFLUSH(3) NEWLIB FFLUSH(3)NAME
4.9 `fflush'--flush buffered file output
SYNOPSIS
#include <stdio.h>
int fflush(FILE *FP);
int _fflush_r(struct _reent *REENT, FILE *FP);
DESCRIPTION
The `stdio' output functions can buffer output before delivering it to
the host system, in order to minimize the overhead of system calls.
Use `fflush' to deliver any such pending output (for the file or
stream identified by FP) to the host system.
If FP is `NULL', `fflush' delivers pending output from all open
files.
Additionally, if FP is a seekable input stream visiting a file
descriptor, set the position of the file descriptor to match next
unread byte, useful for obeying POSIX semantics when ending a process
without consuming all input from the stream.
The alternate function `_fflush_r' is a reentrant version, where the
extra argument REENT is a pointer to a reentrancy structure, and FP
must not be NULL.
RETURNS
`fflush' returns `0' unless it encounters a write error; in that situa‐
tion, it returns `EOF'.
PORTABILITY
ANSI C requires `fflush'. The behavior on input streams is only speci‐
fied by POSIX, and not all implementations follow POSIX rules.
No supporting OS subroutines are required.
SEE ALSOfflush is part of the library. The full documentation for is main‐
tained as a Texinfo manual. If info and are properly installed at your
site, the command
info
will give you access to the complete manual.
NEWLIB April 2010 FFLUSH(3)