(PHP 4 >= 4.3.0, PHP 5, PHP 7)
stream_set_write_buffer — Sets write file buffering on the given stream
$stream
, int $buffer
) : int
Sets the buffering for write operations on the given stream
to buffer bytes.
streamThe file pointer.
buffer
The number of bytes to buffer. If buffer
is 0 then write operations are unbuffered. This ensures that all writes
with fwrite() are completed before other processes are
allowed to write to that output stream.
Returns 0 on success, or another value if the request cannot be honored.
Example #1 stream_set_write_buffer() example
The following example demonstrates how to use stream_set_write_buffer() to create an unbuffered stream.
<?php
$fp = fopen($file, "w");
if ($fp) {
if (stream_set_write_buffer($fp, 0) !== 0) {
// changing the buffering failed
}
fwrite($fp, $output);
fclose($fp);
}
?>
Trying to use stream_set_write_buffer on a local file will always fail according to this note from 2003.
http://grokbase.com/t/php/php-internals/0351gp6xtn/stream-set-write-buffer-does-not-work
Example:
$fp = fopen("localfile.txt", "w");
if (stream_set_write_buffer($fp, 0) !== 0) {
// changing the buffering failed is always true on local files
}