Embedding LuaJIT module into C application

Question

In my application, I have all the Lua libraries exposed from the C backend. Now, I have a need to load a Lua module. The method for this seems to be :

lua_getglobal(L, "require");
lua_pushstring(L, libname);
lua_pcall(L, 1, 0, 0);

which will search the package.path to find <libname>.lua and load it.

Is it possible to build-in the Lua module into the C application (so that the module becomes part of the C application) ? so that I don't have to separately package the Lua module. Somehow I am not able to find any references or examples of this! :(

p.s. I am using LuaJIT-2.0.2, and the library in question is SciLua/Time (uses ffi)

Answer 1

Yes.

luajit -b Module.lua Module_bc.c

will compile a module to bytecode and output a C array initializer containing that bytecode. If you build with shared libraries enabled and export this array from the main executable, require will find it (and will not need to look for Module.lua.)

To test that it is working, set package.path = "" before requireing the module. If it still works, you know the preload is working and it is not just using the Module.lua file from the current directory.

http://luajit.org/running.html

Other things to keep in mind:

• If the module depends on an external file (using io.open), that file still needs to be present. For example some ffi modules try to open a C header file, to pass to ffi.cdef
• You need to keep Module_bc.c in sync with Module.lua, e.g. with a Makefile recipe, or you will see some confusing bugs!