cthreads_thread_detach does not return 0 upon success for Windows builds of Cthreads, which is contrary to its description stating that it "returns 0 on success, non-zero error code on failure."

cthreads_thread_detach makes a call to CloseHandle, which upon success returns a non-zero value and upon failure returns 0. cthreads_thread_detach simply returns this value without inverting it to match the description.

This is a very simple fix.
Line 73 of cthreads.c should be changed from return CloseHandle(thread.wThread); to return CloseHandle(thread.wThread)==0;