Use the native Newton 3.13 library with this header. Check NewtonWorldGetVersion() against NEWTON_MAJOR_VERSION * 100 + NEWTON_MINOR_VERSION before creating a world. A DLL bundled with an unrelated tool may have an older version even when it appears in the 3.13 source tree.

The default dFloat is Single. Define USE_DOUBLE_PRECISION before including Newton.bi only when the native library was compiled with _NEWTON_USE_DOUBLE. Check NewtonWorldFloatSize() against SizeOf(dFloat). The wrong precision changes both by-value calls and structure layouts.

Native Win64 MinGW and Linux amd64 builds of revision 20e799131197faf835c3dda0a36822d7038fb101 have been checked with independent C layouts, both FreeBASIC backends, force callbacks, body motion and world cleanup. The private Windows build uses the engine's MinGW platform branch and fixes its missing Windows timer return; see build_scripts/patches/newton313-mingw-timer.patch. The Linux build uses the original _POSIX_VER_64 branch and needs no Windows timer patch. C callers should include stdbool.h before Newton.h because this older header declares a bool callback without supplying that C type itself. This qualification does not establish compatibility with Newton 4.

Check NewtonCreate() for a null result. Destroy the world once with NewtonDestroy() after finishing all updates. The world owns its bodies. A body keeps its own reference to the collision used to create it, so release the caller's collision reference with NewtonDestroyCollision() after body creation.

NewtonUpdate() completes synchronously. NewtonUpdateAsync() requires NewtonWaitForUpdateToFinish() before reading simulation results or destroying resources. Force callbacks run in the engine's solver threads; use the callback's thread index and synchronize shared application data when more than one solver thread is enabled.