Below I include a suggestion on how to do this sort of version agnostic. Cheers, Henri Live example on Wandbox: https://wandbox.org/permlink/jEn9kNnPB0t5rwjP --- #include #include #include #include #include static int (*lua_os_execute)(lua_State *L) = NULL; static int os_execute(lua_State *L) { // Do whatever printf("Hello Hans!\n"); // Safeguard assert(lua_os_execute != NULL); // Return wrapped return lua_os_execute(L); } LUAMOD_API int luaopen_oslibext(lua_State *L) { lua_getglobal(L, "os"); // Get the address of the original function if (lua_os_execute == NULL) { lua_getfield(L, -1, "execute"); lua_os_execute = lua_tocfunction(L, -1); lua_pop(L, 1); } // Push the new function to overwrite the old one lua_pushcfunction(L, os_execute); lua_setfield(L, -2, "execute"); return 1; } int main(void) { lua_State *L = luaL_newstate(); luaL_openlibs(L); luaopen_oslibext(L); if (luaL_dostring(L, "os.execute([[date]])") != 0) { fprintf(stderr, "%s", lua_tostring(L, -1)); lua_pop(L, 1); } lua_close(L); } On 11/21/19 8:17 PM, Henri Menke wrote:

Dear list,

The following Lua script behaves differently when executed in Lua vs. LuaTeX.

print(os.execute("date"))

It seems that the definition of os_execute in loslibext.c was copied over from Lua 5.1 and not adapted to newer versions.

$ lua5.1 test.lua 0 $ lua5.2 test.lua true exit 0 $ lua5.3 test.lua true exit 0 $ texlua test.lua 0 $ luajit test.lua 0 $ texluajit test.lua 0

As you can see from the example, this comes with the additional complication that LuaJIT has Lua 5.1 behaviour and should also retain that.

Cheers, Henri