c调用lua函数

上代码

function tellme()
	io.write("This is coming from lua.tellme.\n")
end

function square(n)
	io.write("Within callfuncscript.lua fcn square, arg=")
	io.write(tostring(n))
	n = n * n
	io.write(", square=")
	io.write(tostring(n))
	print(".")
	return(n)
end

print("Priming run")

C代码

#include "lauxlib.h"                            /* Always include this when calling Lua */
#include "lualib.h"                             /* Prototype for luaL_openlibs(), */
                                                /*   always include this when calling Lua */

#include "stdlib.h"                             /* For function exit() */
#include "stdio.h"                              /* For input/output */

void bail(lua_State *L, char *msg){
	fprintf(stderr, "\nFATAL ERROR:\n  %s: %s\n\n",
		msg, lua_tostring(L, -1));
	exit(1);
}

int main(void)
{
    lua_State *L;

    L = luaL_newstate();                        /* Create Lua state variable */
    luaL_openlibs(L);                           /* Load Lua libraries */

    if (luaL_loadfile(L, "callfuncscript.lua")) /* Load but don't run the Lua script */
        bail(L, "luaL_loadfile() failed");      /* Error out if file can't be read */

    if (lua_pcall(L, 0, 0, 0))                  /* PRIMING RUN. FORGET THIS AND YOU'RE TOAST */
        bail(L, "lua_pcall() failed");          /* Error out if Lua file has an error */

    printf("In C, calling Lua->tellme()\n");

    lua_getglobal(L, "tellme");                 /* Tell it to run callfuncscript.lua->tellme() */
    if (lua_pcall(L, 0, 0, 0))                  /* Run the function */
        bail(L, "lua_pcall() failed");          /* Error out if Lua file has an error */

    printf("Back in C again\n");
    printf("In C, calling Lua->square(6)\n");

    lua_getglobal(L, "square");                 /* Tell it to run callfuncscript.lua->square() */
    lua_pushnumber(L, 6);                       /* Submit 6 as the argument to square() */
    if (lua_pcall(L, 1, 1, 0))                  /* Run function, !!! NRETURN=1 !!! */
	bail(L, "lua_pcall() failed"); 

    printf("Back in C again\n");
    int mynumber = lua_tonumber(L, -1);
    printf("Returned number=%d\n", mynumber);

    lua_close(L);                               /* Clean up, free the Lua state var */
    return 0;
}