FFLUSH(3) Linux Programmer's Manual FFLUSH(3)NAME
fflush - flush a stream
SYNOPSIS
#include <stdio.h>
int fflush(FILE *stream);
DESCRIPTION
The function fflush forces a write of all user-space buffered data for the given output or update stream via the stream's underlying write
function. The open status of the stream is unaffected.
If the stream argument is NULL, fflush flushes all open output streams.
For a non-locking counterpart, see unlocked_stdio(3).
RETURN VALUE
Upon successful completion 0 is returned. Otherwise, EOF is returned and the global variable errno is set to indicate the error.
ERRORS
EBADF Stream is not an open stream, or is not open for writing.
The function fflush may also fail and set errno for any of the errors specified for the routine write(2).
NOTES
Note that fflush() only flushes the user space buffers provided by the C library. To ensure that the data is physically stored on disk the
kernel buffers must be flushed too, e.g. with sync(2) or fsync(2).
CONFORMING TO
The function fflush() conforms to ANSI X3.159-1989 (``ANSI C'').
SEE ALSO fsync(2), sync(2), write(2), fclose(3), fopen(3), setbuf(3), unlocked_stdio(3)BSD MANPAGE 1993-11-29 FFLUSH(3)
Check Out this Related Man Page
FFLUSH(3) Linux Programmer's Manual FFLUSH(3)NAME
fflush - flush a stream
SYNOPSIS
#include <stdio.h>
int fflush(FILE *stream);
DESCRIPTION
For output streams, fflush() forces a write of all user-space buffered data for the given output or update stream via the stream's underly-
ing write function.
For input streams associated with seekable files (e.g., disk files, but not pipes or terminals), fflush() discards any buffered data that
has been fetched from the underlying file, but has not been consumed by the application.
The open status of the stream is unaffected.
If the stream argument is NULL, fflush() flushes all open output streams.
For a nonlocking counterpart, see unlocked_stdio(3).
RETURN VALUE
Upon successful completion 0 is returned. Otherwise, EOF is returned and errno is set to indicate the error.
ERRORS
EBADF stream is not an open stream, or is not open for writing.
The function fflush() may also fail and set errno for any of the errors specified for write(2).
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
+----------+---------------+---------+
|Interface | Attribute | Value |
+----------+---------------+---------+
|fflush() | Thread safety | MT-Safe |
+----------+---------------+---------+
CONFORMING TO
C89, C99, POSIX.1-2001, POSIX.1-2008.
POSIX.1-2001 did not specify the behavior for flushing of input streams, but the behavior is specified in POSIX.1-2008.
NOTES
Note that fflush() flushes only the user-space buffers provided by the C library. To ensure that the data is physically stored on disk the
kernel buffers must be flushed too, for example, with sync(2) or fsync(2).
SEE ALSO fsync(2), sync(2), write(2), fclose(3), fileno(3), fopen(3), setbuf(3), unlocked_stdio(3)COLOPHON
This page is part of release 4.15 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 https://www.kernel.org/doc/man-pages/.
GNU 2017-09-15 FFLUSH(3)
hi everybody,
when i run and compile this:
printf("test"); fflush(stdout);
nothing appears on screen.
if i try this:
___________________________________
printf("test"); fflush(stdout); sleep(10);
___________________________________
then i can see the output "test"... for 10... (4 Replies)
I'm running Debian ib Bash shell. currently I'm streaming the data from ttyS1 . The data stream is 13 fields comma delimited
cat /dev/ttyS1
02/04/2009,10:57:18,1401.0,7.5,424.9,0.0,0.0,159.8,1401.0,7.5,265.2,34.4,2.5
The data is grouped for specific systems.
02/04/2009,10:57:18 ... (1 Reply)
I am out of idea what to do to resolve the problem!
I need to use the open(file, for.., access) function to write a file.
Never have the situation like that: it is return 0 - zero.
As a result all write(..) going to the screen!
What the problem it could be?
I do not even know... (2 Replies)