Currently, it is very common to develop parts of an application using a scripting language and another part using a lower-level language that has better performance.

In 90% of cases, the lowest-level language chosen is C/C++, so many scripting languages like Python, Perl, and Ruby have some way of communicating with C.

Lua is no different and provides an API so that Lua code can communicate with C code and vice versa.

Lua is an extensible language because we can define functions in C and use them in Lua programs. At the same time, Lua is also an extension language, since it is possible to embed Lua in a C application. The model for communicating with C code offered by Lua is based on a virtual stack, where both the C code and the Lua can push and pop values on the stack.

The functions that manipulate the virtual stack have a lua State structure as a parameter, which stores information about the state of the Lua program. No state information is stored in global variables, so we can have multiple independent lua states.

The didactic example I made available on GitHub, to get run the commands:

git clone https://github.com/terroo/cpp-bind-lua
cd cpp-bind-lua
g++ lua-bind.cpp -shared -fpic -llua -o terroo.so
lua main.lua

Example of how to compile on Windows

g++ lua-bind.cpp -shared -fpic -L C:\path\to\lua.h -L C:\path\to\lauxlib.h -o terroo.dll
lua main.lua

For more information watch this video.

Video is in Portuguese.

cpp lua clanguage