[PD] [comport] crashes on Windows

Hans-Christoph Steiner hans at eds.org
Mon May 22 20:00:47 CEST 2006

First off, I think I have an idea of what's causing the crashes.  I  
think its because [comport] isn't handling when the serial port  
buffer is full.  That's my guess.  [comport] should probably start  
dropping data, with a warning message,  in this condition instead of  
just going down the suicide path...

On May 22, 2006, at 7:35 PM, Christian Klippel wrote:

> hi,
> while at the issue of reading stuff from devices in windows ...
> there are also weird problems with libusb on windows. seems that  
> there are
> some quirks in windows that prevent the hi-speed use of such ports  
> (usb is
> serial as well....)
> im wondering if there are any special calls in the windows api that  
> need to be
> called first, to set certain parameters first, like for buffering?

Have you seen the OVERLAPPED/asynchronous API for Windows?  Check out  
the code in [comport], Piotr Majdak implemented this for Windows, and  
it seems to be a better way to write to the com port.  I think that  
it makes Windows do some buffering (but maybe not enough ;).


> greets,
> chris
> Am Montag, 22. Mai 2006 19:23 schrieb Hans-Christoph Steiner:
>> I have incorporated the "OVERLAPPED" asynchronous mode code for
>> Windows from Piotr Majdak in the [comport], and now it crashes pretty
>> regularly.  I just committed the comport-stress-test.pd, which makes
>> Pd crash within a couple minutes.  It seems to be caused by
>> transferring a lot of data from Pd to the serial port.  FYI: I am
>> using an Arduino to test.
>> I did a little test to see whether its the new code, or whether there
>> were crashes before.  So I compiled revision 1.10, which uses the
>> standard synchronous mode for data transfer.  This version seems to
>> last a bit longer, but it crashes in a much uglier way: it zombies Pd
>> and doesn't let go of the serial port.  So its an improvement, but
>> still, it crashes a lot.
>> Any of you Windows hackers want to take a stab?  I am going to test
>> things on Mac OS X now.
>> .hc
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