[runtime] tapasco_device_access apparently uses Rust type isize (intptr_t in C) as bool

[forflo]

Is there a reason as to why this function does return an int pointer instead of the
bool type from stdbool.h?

As far as I understand the code, the function is used to mark the device as "taken". Is this correct?

[forflo]

The new runtime looks pretty nice by the way.

[jahofmann]

From looking at it, I don't see a reason why it shouldn't for this particular function. For others I've been using < 0 to indicate an error and >= 0 for the result (although some functions use special values to indicate that, e.g. PEID).