Re: [2/3] server: Use tcdrain() instead of tcflush() to implement FlushFileBuffers() for a COM port.

[Alexandre Julliard]

Dmitry Timoshkov  writes:
> MSDN for FlushFileBuffers says:
> Flushes the buffers of a specified file and causes all buffered data to be
> written to a file.
>
> Linux man page says:
> tcdrain() waits until all output written to the object referred to by fd has
> been transmitted.

It's a blocking call, you can't do that on the server side.