> > This exists since Lua 5.2. The culprit is the exit code on Windows having a different format than on unix/posix. The latter has 0-255 as common ground and mostly anything else is undefined. But on Windows the exit code is a 32bit signed integer. > > Now this code: https://github.com/lua/lua/blob/f59e6a93c0ad38a27a420e51abf8f13d962446b5/lauxlib.c#L276-L277 > Treats -1 as a special case, and goes looking for an error message here: https://github.com/lua/lua/blob/f59e6a93c0ad38a27a420e51abf8f13d962446b5/lauxlib.c#L241-L247 > > This results in “No error” in the windows case of -1, since it is a valid exit code. (Sorry for such a late reply...) I don't understand the problem here. The documentation for 'system' in Windows says this: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/system-wsystem?view=vs-2017 A return value of -1 indicates an error, and errno is set to one of the following values: [...] -- Roberto