Oops, sorry for the typo in my first paragraph. Here's my previous post
with a corrected first paragraph:
The initial version of my application (written in scheme) does not use
the sane api directly, but utilizes scanimage and scanadf to perform
scanning. In a future release, I would like to use the sane api
directly for better control.
Although I have a number of years of experience programming C/C++/Java,
I now prefer to use scheme for most of my programming. After briefly
looking at the sane api, I noticed that callbacks are sometimes used. I
am aware of a number of ways and various ffi libraries to handle
callbacks from non-C to C, but it sure would be nice if the sane API was
a little more non-C friendly. Specifically, when a callback pointer is
required, why not also require a "user data" void pointer (or perhaps an
integer id) that would be returned untouched to the callback as a
parameter? This would allow non-C languages to interface more easily to
the sane api. A thin C interface layer could then use one callback
dispatcher to handle all C callbacks. The callback dispatcher could use
stdarg.h to process the other args or perhaps they could be passed to
the callback using a count and array.
In the future, I would be happy to contribute a scheme->sane interface
library to the sane project, but it sure would be nice if the sane api
was more non-C friendly.
Peter
