C++ PlaySound()出现错误

Question

我正在尝试使用C++中的PlaySound()；函数。我想让用户输入他们想要播放的文件。但是当我将变量放在PlaySound()中时，它会给我一个错误。这是代码，

#include <string>
#include <Windows.h>
using namespace std;
int main()
{
    cout << "Enter song name...\nMake sure the song is in the same folder as this program\n";
    string filename;
    getline(cin, filename);
    cout << "Playing song...\n";
    bool played = PlaySound(TEXT(filename), NULL, SND_SYNC);


    return 0;
}

错误，identifier "Lfilename" is undefined 'Lfilename': undeclared identifier我正在使用Microsoft Visual Studio 2019。

Answer 1

不能将TEXT()宏与变量一起使用，只能与编译时字符/字符串文字一起使用。您需要改用std::string::c_str()方法。

此外，TEXT()将L前缀添加到指定标识符的事实意味着您正在为Unicode编译您的项目(即UNICODE是在预处理过程中定义的)，这意味着PlaySound() (作为TCHAR-based宏本身)将映射到PlaySoundW()，后者期望宽强作为输入，而不是窄字符串。因此，您需要调用PlaySoundA()来匹配std::string的使用。

试试这个：

#include <string>
#include <Windows.h>
using namespace std;

int main() {
    cout << "Enter song name...\nMake sure the song is in the same folder as this program\n";
    string filename;
    getline(cin, filename);
    cout << "Playing song...\n";
    bool played = PlaySoundA(filename.c_str(), NULL, SND_SYNC);

    return 0;
}

或者，改用std::wstring，因为Windows更喜欢使用Unicode字符串(基于ANSI的API在内部调用Unicode APIs )：

#include <string>
#include <Windows.h>
using namespace std;

int main() {
    wcout << L"Enter song name...\nMake sure the song is in the same folder as this program\n";
    wstring filename;
    getline(wcin, filename);
    wcout << L"Playing song...\n";
    bool played = PlaySoundW(filename.c_str(), NULL, SND_SYNC);

    return 0;
}