Output using fwrite() is normally buffered at 8K. This
means that if there are two processes wanting to write to the
same output stream (a file), each is paused after 8K of data
to allow the other to write.
stream_set_write_buffer() sets the buffering for write
operations on the given filepointer
stream to buffer
bytes. 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.
The function returns 0 on success, or EOF if the request
cannot be honored.
The following example demonstrates how to use stream_set_write_buffer() to create an
unbuffered stream.