c – 在Lua表中注册C函数

/* actual definitions of modA() and modB() are left as an exercise. */

/* list of functions in the module */
static const luaL_reg modfuncs[] =
{
    { "a",modA},{ "b",modB},{ NULL,NULL }
};

/* module loader function called eventually by require"mod" */  
int luaopen_mod(lua_State *L) {
    luaL_register(L,"mod",modfuncs);
    return 1;
}

这里创建一个名为“mod”的模块,它有两个名为mod.a和mod.b的函数.

引用luaL_register(L,libname,l)的手册：

When called with libname equal to
NULL,it simply registers all
functions in the list l (see 07001)
into the table on the top of the
stack.

When called with a non-null libname,
luaL_register creates a new table t,
sets it as the value of the global
variable libname,sets it as the value
of package.loaded[libname],and
registers on it all functions in the
list l. If there is a table in
package.loaded[libname] or in variable
libname,reuses this table instead of
creating a new one.

In any case the function leaves the table on the top of the stack.

只要表位于堆栈的顶部,luaL_register()可以用于将C函数放在任何表中,通过传递NULL作为其第二个参数.