Failed to post to a semaphore (errno:37)

I’m having a hard problem finding any posts or docs or anything regarding this error message. I’m not noticing any actual noticeable problems based on this, but I am getting the error message when running on hardware. Anyone know what this is about?

I’m running on iOS using MSCorLibs, if that makes a difference.

I’m getting this on iOS as well and would be interested in some clarification. In my case, it happens just before a crash.