Re: Problems sending \x0 with devGpib driver

[Dirk Zimoch <dirk.zimoch@psi.ch>]

On 08.11.2012 18:02, Eric Norum wrote:
> Although not directly related to this thread, an issue I've encountered when attempting to write StreamDevice support for devices with "esoteric" command/reply formats is the inability to provide a custom conversion routine as provided by devGpib.
>
> I went digging through my (very) old e-mail messages and recovered this one proposing an addition to StreamDevice that would allow for user-supplied conversion code.  It's still not quite as general a solution as that provided by the devGpib GPIBCVTIO support but it does allow for message format conversions beyond those provided by StreamDevice.
>
> Perhaps others might find this useful enough that it could be made part of the StreamDevice distribution.
>
> ===============================================================================
> New format string modifier<function_name>.  For example,
>       %<function_name>ld
>       %<function_name>f
>       %<function_name>lf
>
> Where function_name is the name of a conversion function [...]

Hi Eric

This is quite similar to the checksum functions I already have 
implemented, and which use the %<...> format. And if I remember 
correctly, this was indeed based on your ideas.
Maybe I can modify this a bit in order to allow general user supplied 
functions. Checksums would then be a part of the user function model.
I have to think about this and play a bit.

Escaping to user code is of course always "dangerous". You never know 
how much stack the call uses, if it blocks, if it throws exceptions etc.
Dirk