luasocket是怎么调用socket.core的

luasocket中socket.lua文件中

 local socket = require("socket.core") // socket.core?

luasocket中luasocket.c文件中

/*-------------------------------------------------------------------------*\
* Initializes all library modules.
\*-------------------------------------------------------------------------*/
LUASOCKET_API int luaopen_socket_core(lua_State *L) {
    int i;
    base_open(L);
    for (i = 0; mod[i].name; i++) mod[i].func(L);
    return 1;
}

base_open(lua_State *L)的函数源码如下:

static int base_open(lua_State *L) {
    if (socket_open()) {
        /* export functions (and leave namespace table on top of stack) */
        luaL_openlib(L, "socket", func, 0);
#ifdef LUASOCKET_DEBUG
        lua_pushstring(L, "_DEBUG");
        lua_pushboolean(L, 1);
        lua_rawset(L, -3);
#endif
        /* make version string available to scripts */
        lua_pushstring(L, "_VERSION");
        lua_pushstring(L, LUASOCKET_VERSION);
        lua_rawset(L, -3);
        return 1;
    } else {
        lua_pushstring(L, "unable to initialize library");
        lua_error(L);
        return 0;
    }
}

其中,需要注意的是luaL_openlib函数的功能(ps:注意,不是luaL_openlibs函数,在lua官网上面可能找不到该函数的API解释.)

 这样就调用到了C层面的socket的方法，socket的c实现在C_library下面

另外,lua官网有文档说明,如何注册C库.详细的文档请去参考:http://www.lua.org/pil/26.2.html

1 When you extend Lua with C functions, it is a good idea to design your code as a C library, even when you want to register only one C function: 
  Sooner or later (usually sooner) you will need other functions. As usual, the auxiliary library offers a helper function for this job. The luaL_openlib 
  function receives a list of C functions and their respective names and registers all of them inside a table with the library name. 

 

现在已经弄明白在使用C扩展lua的时候,应该将我们的代码设计成为C库.

另外,我这里有一个简单的实例程序:

 1 #include 
 2 #include "./src/lua.h"
 3 #include "./src/lualib.h"
 4 #include "./src/lauxlib.h"
 5 
 6 static int add(lua_State *L)
 7 {
 8 int a,b,c;
 9 a = lua_tonumber(L,1);
10 b = lua_tonumber(L,2);
11 c = a+b;
12 lua_pushnumber(L,c);
13 printf("test hello!!!\r\n");
14 return 1;
15 }
16 static const struct luaL_Reg lib[] =
17 {
18 {"testadd",add},
19 {NULL,NULL}
20 };
21 int luaopen_testlib_core(lua_State *L)  // 注意这里的函数写法
22 {
23 //luaL_register(L,"testlib",lib);   // 1
24 luaL_openlib(L,"testlib",lib,0);    // 2
25 return 1;
26 }
27 
28 ~            

 

 下面给出一个lua脚本:

 

1 #!/usr/bin/env lua
2 require("testlib.core")  // 注意这里的调用,和上面的函数写法是相关联的
3 c = testlib.testadd(15,25)
4 print("The result is ",c);
5 ~                          

 

 

 到这里就很明白了,如果我在上面的C源码中使用的是luaopen_testlib(lua_State *L),那么在下面的lua脚本中直接require("testlib")就可以了.

 但是如果是像我上面的这种命名方式,那么就需要像我这么做.而luasocket中出现的require("socket.core"),就是这么出现的.