我相信以下有一个理性的解释,但我有点困惑.
问题在于创建一个_TCHAR [CONSTANT],一个_TCHAR *的函数,并连接它们并返回结果.
由于某种原因,来自_tmain()的whatTheHeck()的调用返回乱码.
_TCHAR* whatTheHeck(_TCHAR* name) {
_TCHAR Buffer[BUFSIZE];
DWORD dwRet;
dwRet = GetCurrentDirectory(BUFSIZE,Buffer);
_TCHAR* what = new _TCHAR[BUFSIZE];
what = _tcscat(Buffer,TEXT("\\"));
what = _tcscat(what,name);
return what;
}
int _tmain(int argc,_TCHAR* argv[]) {
_TCHAR* failure = whatTheHeck(TEXT("gibberish);")); // not again ..
_tprintf(TEXT("|--> %s\n"),failure);
_TCHAR* success = createFileName(TEXT("readme.txt")); // much better
_tprintf(TEXT("|--> %s\n"),success);
return 0;
}
相比之下,当堆东西按预期工作时.
_TCHAR* createFileName(_TCHAR* name) {
_TCHAR* Buffer = new _TCHAR[BUFSIZE];
DWORD dwRet;
dwRet = GetCurrentDirectory(BUFSIZE,Buffer);
Buffer = _tcscat(Buffer,TEXT("\\"));
Buffer = _tcscat(Buffer,name);
return Buffer;
}
为什么有区别？
是因为_tcscat()连接内存地址而不是其内容并返回清除堆栈？
解决方法
你的代码有很多问题.让我们分开,我们应该：
_TCHAR* whatTheHeck(_TCHAR* name) // We're inside a local scope
{
_TCHAR Buffer[BUFSIZE]; // "Buffer" has automatic storage
_TCHAR* what = new _TCHAR[BUFSIZE]; // "what" points to newly allocated dyn. memory
what = _tcscat(Buffer,TEXT("\\")); // Oh no,we overwrite "what" - leak!
// Now what == Buffer.
what = _tcscat(what,name); // Equivalent to "_tcscat(Buffer,name)"
return Buffer; // WTPF? We're returning a local automatic!
}
正如你所看到的,你们都是引起内存泄漏的一个有意思和鲁莽的新功能,你也在一生之后返回一个本地对象的地址！
我强烈推荐
阅读documentation for strcat,了解“来源”和“目的地”,>不使用strcat,而是像strncat一样更安全的版本,>不使用strncat,而是std :: string.
