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Calling Lua function from C++

时间:2015-09-03 10:22:55      阅读:162      评论:0      收藏:0      [点我收藏+]

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http://blog.csdn.net/cnjet/article/details/5909519

 

Calling Lua function from c++ is very simple. Value passing between c++ and Lua goes through stack, Lua C API provides a convenience ways for you to call Lua function from C. To call Lua function, you need to specify:

1. Function Name.
2. Parameters of function call.
3. Return values expected ( Lua function support multiple results reture)

Let say my lua function name call f in last.lua, takes 2 parameters.

-- last.lua
function f (x, y)
    return (x^2 * math.sin(y))/(1 - x)
end

I perform function call from c++ like this:

01 //last.cc
02 # extern "C" {
03 # #include "lua.h"
04 # #include "lualib.h"
05 # #include "lauxlib.h"
06 # } 
07  
08 int main()
09 {
10     double z;
11     lua_State *L = lua_open();
12     luaL_openlibs(L);
13     if (luaL_loadfile(L, "last.lua") || lua_pcall(L, 0, 0, 0)) {
14         printf("error: %s", lua_tostring(L, -1));
15         return -1;
16     }
17  
18     lua_getglobal(L, "f");
19     if(!lua_isfunction(L,-1))
20     {
21         lua_pop(L,1);
22         return -1;
23     }
24     lua_pushnumber(L, 21);   /* push 1st argument */
25     lua_pushnumber(L, 31);   /* push 2nd argument */
26  
27     /* do the call (2 arguments, 1 result) */
28     if (lua_pcall(L, 2, 1, 0) != 0) {
29         printf("error running function `f‘: %s/n",lua_tostring(L, -1));
30         return -1;
31     }
32  
33     /* retrieve result */
34     if (!lua_isnumber(L, -1)) {
35         printf("function `f‘ must return a number/n");
36         return -1;
37     }
38     z = lua_tonumber(L, -1);
39     printf("Result: %f/n",z);
40     lua_pop(L, 1);
41     lua_close(L);
42  
43     return 0;
44 }

Compile it with g++ like this:

g++ -o last{,.cc} -llua -ldl

The results:

Result: -12.158958

Brief explanation of the C++ codes above:
First, I trigger lua_getglobal to get the function name, then I push 2 parameters to stack. I make lua_pcall by telling Lua I have 2 params and expect 1 value return. Upon success, I retrieve the return value from the top of the stack.

Calling Lua function from C++

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原文地址:http://www.cnblogs.com/gamekk/p/4779924.html

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