You should compile with warnings turned up, you got a bunch of little errors.

example:

in nv_Space_broadphase you have a for loop going over space->bodies->size using 'j' and then inside that for loop you use 'j' again, and you do that a couple times.

also, there's quiet a few instances of signed / unsigned mismatching in for loops

I like this library and am testing it in my 2D game. Here are some recommendations:

• I recommend including CMAKE build because it is easy to use and cross platform. I could not build the examples with the custom build. Keeps giving errors. A cmake build would make it easier for me to drop it into my projects.
• I recommend using -Wall build warnings. There were alot of errors when building. I built it with -Wall on C99 standard.
• I recommend adding more documentation and explanation on various abstract features like constraint and awake/sleep. There is not much understanding in the position_iters and velocity_iters field of the nv_Space_step API.
• I recommend adding more simple getting started samples. I found the example added to be very difficult to understand.
• I recommend updating the APIs to make it more friendly to Game development. I am working on a flat plane 2D game and I had to manually zero the gravity variable of the Space object because that was not desired in my Game. Making the gravity force optional in the nv_Space_new() API would have been better. I had to write my own friction logic and clamp to zero logic (once the velocity is under a certain value, set it to zero) to make the feel of the physics more 2D game friendly. Would be awesome to include this as additional API.