|FFLUSH(3)||Linux Programmer's Manual||FFLUSH(3)|
int fflush(FILE *stream);
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).
- 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).
|fflush ()||Thread safety||MT-Safe|
POSIX.1-2001 did not specify the behavior for flushing of input streams, but the behavior is specified in POSIX.1-2008.