禁止显示“使用'X'属性是C ++ 17扩展名”警告

Question

I'm using Qt Creator and I have CONFIG += c++17 in my .pro file, and I'm using the nodiscard attribute where appropriate. However, the compiler still needlessly warns that use of the '[[nodiscard]]' attribute is a C++17 extension .

Is there a way to suppress that particular warning? Or even all warnings of the type "X is a C++XX extension"? I've looked everywhere for a flag to include in CXXFLAGS without success.

I'm using Qt Creator version 4.9.2 and g++ version 8.3.0

Answer 1

Since Qt 5.12 you can use config flag CONFIG += c++17

Before Qt 5.12 you need to add compiler flags through qmake flags: QMAKE_CXXFLAGS += -std=c++17 for GCC & MinGW and QMAKE_CXXFLAGS += /std:c++latest or QMAKE_CXXFLAGS += /std:c++17 <- depends on MSVC compiler you are using.

Here is Qt qmake manual variable reference for more info

And Gerrit code review of task QTBUG-67527 for even more info

After you have added this flags:

1. run qmake on the project again

2. clean your project. (delete shadow build folder if necessary)

3. rebuild your project