使用MinGW / Code :: Blocks构建SDL时出现不一致的“未定义引用...”错误

Question

我有3个独立文件，两个是.c文件，一个是.cpp。

当我尝试在Code :: Blocks中构建/运行其中一个.c文件时，我得到一个“未定义的对'SDL_main'的引用”构建错误。

第一个文件（我们称之为SDLtest1.c）构建并运行：

//-----< includes >-----//
// Using SDL and standard IO
#include "SDL.h"
#include <stdio.h>

//-----< globals and constants >-----//
//screen dimension constants
typedef enum {
    SCREEN_WIDTH = 640,
    SCREEN_HEIGHT = 480,
}SCREEN_DIMENSIONS;

//-----< main >-----//
int main(int argc, char* argv[]) {
    // The window we'll be rendering to
    SDL_Window* window = NULL;

    // The surface contained by the window
    SDL_Surface* screenSurface = NULL;

    // Initialize SDL
    if( SDL_Init( SDL_INIT_VIDEO ) < 0 ) {
        printf( "SDL could not be initialized! SDL_Error: %s\n", SDL_GetError() );
    }
    else {
        // Create Window
        window = SDL_CreateWindow("SDL Tutorial",
                SDL_WINDOWPOS_UNDEFINED,
                SDL_WINDOWPOS_UNDEFINED,
                SCREEN_WIDTH,
                SCREEN_HEIGHT,
                SDL_WINDOW_SHOWN);
        if( window == NULL ){
            printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );
        } else {
        // Get window surface
        screenSurface = SDL_GetWindowSurface( window );

        // Fill the surface white
        SDL_FillRect( screenSurface, NULL, SDL_MapRGB( screenSurface->format, 0xFF, 0xFF, 0xFF) );

        // Update the surface
        SDL_UpdateWindowSurface( window );

        // Wait two seconds
        SDL_Delay( 2000 );
        }
    }

    // Destroy Window
    SDL_DestroyWindow( window );

    // Quit SDL subsystems
    SDL_Quit();

    return 0;
}

我还有一个构建和运行的.cpp文件（让我们称之为SDLexample.cpp）：

//Using SDL and standard IO
#include <SDL.h>
#include <stdio.h>

//Screen dimension constants
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;

//Starts up SDL and creates window
bool init();

//Loads media
bool loadMedia();

//Frees media and shuts down SDL
void close();

//The window we'll be rendering to
SDL_Window* gWindow = NULL;

//The surface contained by the window
SDL_Surface* gScreenSurface = NULL;

//The image we will load and show on the screen
SDL_Surface* gHelloWorld = NULL;

bool init()
{
    //Initialization flag
    bool success = true;

    //Initialize SDL
    if( SDL_Init( SDL_INIT_VIDEO ) < 0 )
    {
        printf( "SDL could not initialize! SDL_Error: %s\n", SDL_GetError() );
        success = false;
    }
    else
    {
        //Create window
        gWindow = SDL_CreateWindow( "SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN );
        if( gWindow == NULL )
        {
            printf( "Window could not be created! SDL_Error: %s\n", SDL_GetError() );
            success = false;
        }
        else
        {
            //Get window surface
            gScreenSurface = SDL_GetWindowSurface( gWindow );
        }
    }

    return success;
}

bool loadMedia()
{
    //Loading success flag
    bool success = true;

    //Load splash image
    gHelloWorld = SDL_LoadBMP( "02_getting_an_image_on_the_screen/hello_world.bmp" );
    if( gHelloWorld == NULL )
    {
        printf( "Unable to load image %s! SDL Error: %s\n", "02_getting_an_image_on_the_screen/hello_world.bmp", SDL_GetError() );
        success = false;
    }

    return success;
}

void close()
{
    //Deallocate surface
    SDL_FreeSurface( gHelloWorld );
    gHelloWorld = NULL;

    //Destroy window
    SDL_DestroyWindow( gWindow );
    gWindow = NULL;

    //Quit SDL subsystems
    SDL_Quit();
}

int main( int argc, char* args[] )
{
    //Start up SDL and create window
    if( !init() )
    {
        printf( "Failed to initialize!\n" );
    }
    else
    {
        //Load media
        if( !loadMedia() )
        {
            printf( "Failed to load media!\n" );
        }
        else
        {
            //Apply the image
            SDL_BlitSurface( gHelloWorld, NULL, gScreenSurface, NULL );

            //Update the surface
            SDL_UpdateWindowSurface( gWindow );

            //Wait two seconds
            SDL_Delay( 2000 );
        }
    }

    //Free resources and close SDL
    close();

    return 0;
}

但是第三个文件（SDLtest2.c）无法构建如下：

C:\MinGW\lib\libSDL2main.a(SDL_windows_main.o):SDL_windows_main.c|| undefined reference to `SDL_main'|
||=== Build finished: 1 errors, 0 warnings (0 minutes, 0 seconds) ===|

第三档：

//-----< includes >-----//
#include "SDL.h"
#include <stdio.h>

//-----< preprocessor directives >-----//
#define TRUE 1
#define FALSE 0
typedef int BOOLEAN;

//-----< globals and constants >-----//
typedef enum {
    SCREEN_WIDTH = 640,
    SCREEN_HEIGHT = 480
}SCREEN_DIMENSION;

// The window we'll be rendering to
SDL_Window* gWindow = NULL;

// The surface contained by the window
SDL_Surface* gScreenSurface = NULL;

// The image we will load and show on the screen
SDL_Surface* gHelloWorld = NULL;

//-----< forward declarations >-----//
// Starts up SDL and creates window
BOOLEAN init();

// Loads media
BOOLEAN loadMedia();

// Frees media and shuts down SDL
void close();

//-----< main >-----//
int main(int argc, char* args[]) {
    // Start up SDL and create window
    if( !init() ) {
        printf( "Failed to initialize!\n" );
    }
    else
    {
        // Load media
        if( !loadMedia() ) {
            printf( "Failed to load media!\n" );
        }
        else
        {
            // Apply the image
            SDL_BlitSurface( gHelloWorld, NULL, gScreenSurface, NULL );

            // Update the surface
            SDL_UpdateWindowSurface( gWindow );

            // Wait two seconds
            SDL_Delay( 2000 );
        }
    }

    // Free resources and close SDL
    close();

    return 0;
}


//-----< function definitions >-----//

BOOLEAN init() {
    // Initialization flag
    BOOLEAN success = TRUE;

    // Initialize SDL
    if( SDL_Init( SDL_INIT_VIDEO ) < 0 ) {
        printf( "SDL could not initialize! SDL_Error: %s\n", SDL_GetError() );
        success = FALSE;
    }
    else
    {
        // Create a window
        gWindow = SDL_CreateWindow( "SDL Tutorial",
                SDL_WINDOWPOS_UNDEFINED,
                SDL_WINDOWPOS_UNDEFINED,
                SCREEN_WIDTH,
                SCREEN_HEIGHT,
                SDL_WINDOW_SHOWN);
        if( gWindow == NULL ) {
            printf( "Window could not be created! SDL_Error: %s\n", SDL_GetEror() );
            success = FALSE;
        }
        else
        {
            //Get window surface
            gScreenSurface = SDL_GetWindowSurface( gWindow );
        }

    return success;
}

BOOLEAN loadMedia() {
    // Loading success flag
    BOOLEAN success = TRUE;

    // Load splash image
    gHelloWorld = SDL_LoadBMP( "02_getting_an_image_on_the_screen/hello_world.bmp" );
    if( gHelloWorld == NULL ) {
        printf( "Unable to load image %s! SDL Error: %s\n", "02_getting_an_image_on_the_screen/hello_world.bmp", SDL_GetError() );
        success = FALSE;
    }

    return success;
}

void close() {
    // Deallocate surface
    SDL_FreeSurface( gHelloWorld );
    gHelloWorld = NULL;

    // Destroy window
    SDL_DestroyWindow( gWindow );
    gWindow = NULL;

    //Quit SDL subsystems
    SDL_Quit();
}

我一遍又一遍地查看第三个文件，因为错别字可能导致构建错误并且没有找到任何错误（尽管我肯定可能错过了一个）。我已经查看了类似的论坛问题，但没有一个完全匹配，并且其他两个文件构建和运行成功的事实告诉我，问题不在于我的Code :: Blocks或SDL设置。

我知道这一切都需要关注并感谢任何人提供的任何帮助。