转载请注明出处：
http://www.cnblogs.com/darkknightzh/p/5804924.html
原始网址：
http://www.troubleshooters.com/codecorn/lua/lua_lua_calls_c.htm
1. 新建hellofunc.c，输入：
/* hellofunc.c (C) 2011 by Steve Litt
* gcc -Wall -shared -fPIC -o Cfunc.so -I/usr/include/lua5.1 -llua5.1 hellofunc.c
* Note the word " Cfunc " matches the string after the underscore in
* function luaopen_ Cfunc(). This is a must.
* The -shared arg lets it compile to .so format.
* The -fPIC is for certain situations and harmless in others.
* On your computer, the -I and -l args will probably be different.
*/ #include <lua5./lua.h> /* Always include this */
#include <lua5./lauxlib.h> /* Always include this */
#include <lua5./lualib.h> /* Always include this */ static int isquare(lua_State *L) /* Internal name of func */
{
float rtrn = lua_tonumber(L, -); /* Get the single number arg */
printf("Top of square(), nbr=%f\n",rtrn);
lua_pushnumber(L,rtrn*rtrn); /* Push the return */
return ; /* One return value */
}
static int icube(lua_State *L){ /* Internal name of func */
float rtrn = lua_tonumber(L, -); /* Get the single number arg */
printf("Top of cube(), number=%f\n",rtrn);
lua_pushnumber(L,rtrn*rtrn*rtrn); /* Push the return */
return ; /* One return value */
} /* Register this file's functions with the
* luaopen_libraryname() function, where libraryname
* is the name of the compiled .so output. In other words
* it's the filename (but not extension) after the -o
* in the cc command.
*
* So for instance, if your cc command has -o power.so then
* this function would be called luaopen_power().
*
* This function should contain lua_register() commands for
* each function you want available from Lua.
*
*/
int luaopen_Cfunc(lua_State *L){
lua_register(
L, /* Lua state variable */
"testsquare", /* func name as known in Lua */
isquare /* func name in this file */
);
lua_register(L,"testcube",icube);
return ;
}
2. 在ubuntu的终端中生成.so：
gcc -Wall -shared -fPIC -o Cfunc.so hellofunc.c
说明：luaopen_ XXX对应于上面-o后面的XXX.so的XXX。供LUA代码中require“XXX”来调用。
3. 新建myLUA.lua，输入：
require("Cfunc")
print(testsquare(1.414213598))
print(testcube())
4. 终端中输入:
lua myLUA.lua
5. 结果：
说明：电脑上装了lua5.1和lua5.2.默认的是lua5.2.使用lua myLUA.lua后，提示：
经过查找，发现默认的是lua5.2。然后直接使用lua5.1 myLUA.lua后，显示的就是正确的结果（如果使用lua5.2 myLUA.lua，显示的就是上面的错误）。当然，如果装了torch，torch默认的也是5.1的话，使用th myLUA.lua后，也能显示正确的结果，如下：
