LNK2019-无法解析的外部符号-C ++-SDL2库 [英] LNK2019 - unresolved external symbol - C++ - SDL2 Library

问题描述

我正在尝试初始化我的游戏窗口，无法克服此错误.我已经尝试过:

I am trying to initialize my game window and can't get past this error. I have tried:

• 一遍又一遍地检查我所有的代码是否存在语法错误
• 检查SDL2库是否正确包含在我的项目中

请参阅以下代码供您参考:

Please see below code for your reference:

头文件:

#ifndef Game_hpp
#define Game_hpp
#include "SDL.h"
#include <iostream>

class Game
{
public:
    Game();
    ~Game();

    void init(const char* title, int xpos, int ypos, int width, int height, bool fullscreen);
    void handleEvents();
    void update();
    void render();
    void clean();

    bool running()
    {
        return isRunning;
    }

private:
    bool isRunning;
    SDL_Window *window;
    SDL_Renderer *renderer;
};

#endif /* Game_hpp */

Game.cpp-定义函数的地方

 #include "Game.h"

Game::Game()
{}

Game::~Game()
{}

void Game::init(const char *title, int xpos, int ypos, int width, int height, bool fullscreen)
{
    int flags = 0;
    if (fullscreen)
    {
        flags = SDL_WINDOW_FULLSCREEN;
    }

    if (SDL_Init(SDL_INIT_EVERYTHING) == 0)
    {
        std::cout << "Subsystems Initialised..." << std::endl;

        window = SDL_CreateWindow(title, xpos, ypos, width, height, flags);
        if (window)
        {   
            std::cout << "Window Created" << std::endl;
        }

        renderer = SDL_CreateRenderer(window, -1, 0);
        if (renderer)
        {
            SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
            std::cout << "Renderer Created" << std::endl;
        }

        isRunning = true;
    }

    else
    {
        isRunning = false;
    }
}

void Game::handleEvents()
{
    SDL_Event event;
    SDL_PollEvent(&event);
    switch (event.type)
    {
        case SDL_QUIT:
            isRunning = false;
            break;

        default:
            break;
    }
}

void Game::update()
{}

void Game::render()
{
    SDL_RenderClear(renderer);
    //this is where we add stuff to render
    SDL_RenderPresent(renderer);
}

void Game::clean()
{
    SDL_DestroyWindow(window);
    SDL_DestroyRenderer(renderer);
    SDL_Quit();
    std::cout << "Game Cleaned." << std::endl;
}

主要功能:

#include "Game.h"

Game *game = nullptr;

int main(int argc, const char * argv[])
{
    game = new Game();

    game->init("BirchEngine", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 800, 600, false);

    while (game->running())
    {
        game->handleEvents();
        game->update();
        game->render();
     }

    game->clean();

    return 0;
}

我得到的错误:

1> SDL2main.lib(SDL_windows_main.obj):错误LNK2019:函数main_utf8中引用了未解析的外部符号SDL_main

1>SDL2main.lib(SDL_windows_main.obj) : error LNK2019: unresolved external symbol SDL_main referenced in function main_utf8

1> C:\ Dev \ 2D_GameEngine \ x64 \ Debug \ 2D_GameEngine.exe:致命错误LNK1120:1个未解决的外部组件

1>C:\Dev\2D_GameEngine\x64\Debug\2D_GameEngine.exe : fatal error LNK1120: 1 unresolved externals

非常感谢您的帮助！

推荐答案

SDL(不幸的是，IMO)在重新定义 main 的地方做了这个奇怪的事情，以便抽象出特定于平台的条目细节指向应用程序.为了不利用此功能，请执行以下操作.在包含 SDL.h 之前，首先定义 SDL_MAIN_HANDLED .

SDL (unfortunately, IMO) does this strange thing where they redefine main, in order to abstract away platform specific details of the entry point in applications. In order to not utilize this feature, perform the following. Before including SDL.h, first define SDL_MAIN_HANDLED.

#define SDL_MAIN_HANDLED
#include <SDL2/SDL.h>

禁止重新定义 main .然后，在 main 中，在使用SDL进行任何其他操作之前，请调用此函数

That inhibits the redefinition of main. Then, in main, before doing anything else with SDL, call this function

SDL_SetMainReady();

这将执行SDL所需的任何初始化(当前除了将名为 SDL_MainIsReady 的全局变量设置为true以外，什么都不做).

That will do any initialization that is needed by SDL (currently does nothing other than setting a global variable named SDL_MainIsReady to true).

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