在使用GDI+时,我们有时用new建立某些类的指针,在用delete释放内存时会出现异常,如下面的代码:
FontFamily fontFamily(L"Arial"); Gdiplus::Font font(&fontFamily, 8, FontStyleRegular, UnitPixel); RectF rectf(10.0f, 10.0f, 500.0f, 500.0f); SolidBrush solidbrush(Color(255, 0, 0, 0)); INT count = 0; INT found = 0; WCHAR familyName[LF_FACESIZE]; WCHAR* familyList = NULL; FontFamily* pFontFamily = NULL; InstalledFontCollection installedFontCollection; count = installedFontCollection.GetFamilyCount(); pFontFamily = new FontFamily[count]; installedFontCollection.GetFamilies(count, pFontFamily, &found); familyList = new WCHAR[count*(sizeof(familyName) + 3)]; ZeroMemory(familyList, count*(sizeof(familyName) + 3)); for (INT j = 0; j < count; ++j) { pFontFamily[j].GetFamilyName(familyName); StringCchCatW(familyList, count*(sizeof(familyName) + 3), familyName); StringCchCatW(familyList, count*(sizeof(familyName) + 3),L", " ); } gs->DrawString(familyList, -1, &font, rectf, NULL, &solidbrush); delete pFontFamily; delete familyList;
上面代码运行,delete会出错,通过断点发现异常点如下图:
由红线可知代码异常是出现在删除一个对象(FontFamily)指针,而pFontFamily是一个FontFamily对象数组指针,
解决方法是把:
delete pFontFamily;
改成:
delete []pFontFamily;
用new建立其它类指针在delete时出错也是,要注意你是建立的对象指针(p=new FontFamily)还是对象数组指针(p=new FontFamily[count]),
对象指针用:delete p
对象数组指针用delete []p