Hi all, I wanted a way (on Linux) to access magstripe (credit card) readers and similar devices which pretend to be a keyboard (including usb number (10-key) pads and supposedly also barcode readers) without suffering the ills of "must be attached to terminal" and "oops, dvorak keymap garbles the credit card" info.
I determined that libhid is just the thing. It now has sort of a perl binding. http://scratchcomputing.com/svn/Linux-USBKeyboard/trunk/examples/numpad.pl It's basically just a constructor (create()), destructor, and the _char() method at this point. Where I'm stuck is on whether to attempt doing any more of the implementation in C or just to wrap _char() with some looping in Perl. The cpu usage of the above app is *very* low (not at all what you would expect from while(1), but it appears that libhid blocks a bit.) I thought about having _char() return undef, but I'm a bit rusty on how to do that and that just means having to always check defined() vs the maybe-more-convenient "zero length string" we get with this setup. Any advice? Anybody have such a device (or second usb keyboard) and want to try it? Is libhid on windows? I'll be heading to bed now with visions of a wx calculator running in the background and connected to the numpad despite the lack of keyboard focus :-D. I'm thinking a filehandle-like usage would be really cool, but I'm having a hard time finding a reason to write any more C code (because I could just pipe-open a child for reading.) Thanks, Eric -- "Ignorance more frequently begets confidence than does knowledge." -- Charles Darwin --------------------------------------------------- http://scratchcomputing.com ---------------------------------------------------
