[fpc-pascal] USB Human Interface Devices

[Stefan V. Pantazi]

On 8/16/19 11:11 AM, James Richters wrote:
>>> Remember that interrupt reads are  blocking so the way to deal with them is to put them away from the main thread, in their own thread. The moment something is available from the device, then the main thread of your application is signaled to read a buffer with the device report data. So, I can see some thread programming in your future or,

I see I did not finish my sentence. What I had in mind is that you could 
use a library that already implements (using a thread I assume) a call 
with a timeout. I checked and it looks like the original libusb call 
that I used did have a timeout parameter that I hardcoded to 0 (infinite 
timeout). libusb report a timeout as an error code. That did not sit 
well with me and I preferred to use threads instead of time-out mechanism.

 > Is there another way to do a read that has a timeout?

yes, it took only a few minutes to add the time-out parameter to the 
libusbhid_interrupt_read call. Have a look at the github repository for 
the updated version.

> 
> Can I even do threads in a console program?   

Sure you can, here is one of the simplest example you can start with 
should you ever need to have multiple threads in your programs.

https://github.com/graemeg/freepascal/blob/master/packages/fcl-base/examples/threads.pp


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