NAME

fflush, fpurge — flush a stream

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <stdio.h>

int
fflush(FILE *stream);

int
fpurge(FILE *stream);

DESCRIPTION

The function fflush() synchronizes the state of the given stream in light of buffered I/O. For output or update streams it writes all buffered data via the stream's underlying write function. For input streams it seeks to the current file position indicator via the stream's underlying seek function. The open status of the stream is unaffected.

If the stream argument is NULL, fflush() flushes all open streams.

The function fpurge() erases any input or output buffered in the given stream. For output streams this discards any unwritten output. For input streams this discards any input read from the underlying object but not yet obtained via getc(3); this includes any text pushed back via ungetc(3).

RETURN VALUES

Upon successful completion 0 is returned. Otherwise, EOF is returned and the global variable errno is set to indicate the error.

ERRORS

[EBADF]

The stream argument is not an open stream.

The function fflush() may also fail and set errno for any of the errors specified for the routines write(2) and lseek(2).

SEE ALSO

write(2), fclose(3), fopen(3), lseek(2), setbuf(3)

STANDARDS

The fflush() function conforms to ISO/IEC 9899:1990 (“ISO C90”) and Version 3 of the Single UNIX Specification (“SUSv3”).