c++ - SDL_FillRect 中的 SDL2 段错误

Question

终端输出:

    > ./a.out 
    bla1
    Speicherzugriffsfehler

Speicherzugriffsfehler 在德语中的意思基本上是段错误。

当我使用全局变量，或将函数中的代码复制粘贴到 main 中时，它就可以正常工作。我不知道它为什么坏了。

在 Linux Mint 16 上编译:g++ sdl.cpp -lSDL2

源代码:

#include <iostream>
#include <SDL2/SDL.h>

#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480

using namespace std;

bool init_SDL(SDL_Window *window, SDL_Surface *windowSurface);
void close_SDL(SDL_Window *window, SDL_Surface *image);

int main(int argc, char *argv[])
{
    SDL_Window *window = NULL;
    SDL_Surface *windowSurface = NULL;
    SDL_Surface *image = NULL;

    if(!init_SDL(window, windowSurface)){
        cout << "Failed to initialize SDL" << endl;
    }
    else{
        cout << "bla1" << endl;
        SDL_FillRect(windowSurface, NULL, SDL_MapRGB(windowSurface->format, 0xFF, 0xFF, 0xFF));
        cout << "bla2" << endl;
        SDL_UpdateWindowSurface(window);
        cout << "bla3" << endl;
        SDL_Delay(2000);
    }
    close_SDL(window, image);

    EXIT_SUCCESS;
}

bool init_SDL(SDL_Window *window, SDL_Surface *windowSurface){
    bool success = true;
    if(SDL_Init(SDL_INIT_VIDEO) < 0){
        cout << "SDL failed to initialize! SDL_Error: " << SDL_GetError() << endl;
        success = false;
    }
    else{
        window = SDL_CreateWindow("SDL Test", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
        if(window == NULL){
            cout << "Failed to create window! SDL_Error: " << SDL_GetError() << endl;
            success = false;
        }
        else{
            windowSurface = SDL_GetWindowSurface(window);
        }
    }
    return success;
}

void close_SDL(SDL_Window *window, SDL_Surface *image){
    SDL_FreeSurface(image);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return;
}

Answer 1

我在 reddit 上找到了解决方案。这解决了它:

bool init_SDL(SDL_Window *&window, SDL_Surface *&windowSurface)

我需要通过引用传递指针，因为指针本身在函数中被操纵。否则他们仍然会指向 main 中的 null。