属性＆＃39; fallthrough＆＃39;不能在这种情况下应用

Question

我试图在visual studio 2017中使用c ++ 17 MediaSource mainSource = new ExtractorMediaSource(firstVideoUri, ...); MediaSource secondSource = new ExtractorMediaSource(secondVideoUri, ...); MediaSource thirdSource = new ExtractorMediaSource(thirdVideoUri, ...); // Plays the first video, then second & third video. ConcatenatingMediaSource concatenatedSource = new ConcatenatingMediaSource(mainSource, secondSource, thirdSource); 属性：

[[fallthrough]]

但是我收到编译错误：

  

属性＆＃39; fallthrough＆＃39;不能在这种情况下应用

这似乎是你可以使用Qt::ItemFlags flags = Qt::ItemIsSelectable; switch (index.column()) { case 0: flags |= Qt::ItemIsUserCheckable; break; case 2: [[fallthrough]] case 3: [[fallthrough]] case 4: flags |= Qt::ItemIsEditable; break; } return flags; 的唯一背景......我做错了什么？

Answer 1

给出了这个神秘错误，因为[[fallthrough]]属性需要分号来终止它们。将case语句重写为

[[fallthrough]]

解决了错误。