C++ 从 C 调用 Lua 函数：最小示例导致 LUA_ERRRUN

当返回值lua_pcall是not LUA_OK时，错误消息将被推送到堆栈的顶部.

可以使用像lua_tostring这样的函数来操作该值，以便在C中使用.

result = lua_pcall(L, 0, 0, 0);

if (result != LUA_OK) {
    fprintf(stderr, "Error running lua: %s\n", lua_tostring(L, -1));
    exit(1);
}

(You can also propagate the error with 100, but that may defeat the purpose of the protected call.)

执行此操作会显示错误

Error running lua: attempt to call a nil value

这意味着lua_getglobal(L, "hello");将nil推入堆栈.

(Note that we only get this far because 100 is the inverse condition to check for.)

全局变量hello的值是nil，因为包含其定义的chunk从未执行过.也就是说，luaL_loadfile个(最终是lua_load个)只有loads个块，它不执行它们.

加载块后，您可以像执行任何其他函数一样执行它(lua_call等).

例如:

#include <stdio.h>
#include <stdlib.h>

#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"

int
main(void) {
    lua_State *L = luaL_newstate();

    luaL_openlibs(L);

    int status;
    int result;

    status = luaL_loadfile(L, "play.lua"); /* load the chunk */
    if (status != LUA_OK) {
        fprintf(stderr, "Could not load 'play.lua': %s\n", lua_tostring(L, -1));
        exit(1);
    }

    result = lua_pcall(L, 0, 0, 0); /* execute the chunk */
    if (result != LUA_OK) {
        fprintf(stderr, "Error running lua: %s\n", lua_tostring(L, -1));
        exit(1);
    }

    lua_getglobal(L, "hello");
    if (!lua_isfunction(L, -1)) {
        fprintf(stderr, "ERROR: Not a function!\n");
        exit(1);
    }

    result = lua_pcall(L, 0, 0, 0);
    if (result != LUA_OK) {
        fprintf(stderr, "Error running lua: %s\n", lua_tostring(L, -1));
        exit(1);
    }

    puts("lua ran fine");
    lua_close(L);
}

输出:

Hello World!

lua ran fine

请注意，luaL_dofile是定义为

(luaL_loadfile(L, filename) || lua_pcall(L, 0, LUA_MULTRET, 0))

并且是加载和执行块的便捷方式.