无法在QtCreator中使用g ++ 7.2使用c ++ 17功能 [英] Can't use c++17 features using g++ 7.2 in QtCreator
问题描述
我最近将gcc和g ++更新到了7.2版.我想特别尝试std::experimental::any和std::variant，并且我正在QtCreator中使用Qt 5.9.1.
I have recently updated gcc and g++ to version 7.2. I would like to try out std::experimental::any and std::variant in particular, and I am using Qt 5.9.1 in QtCreator.
到目前为止，我已经将其写在项目文件中:
So far I have written this in the project file:
CONFIG += c++17
我在正确的位置添加了正确的标题:
And I have added the correct headers in the correct places:
#include <variant>
#include <experimental/any>
任何人都可以正常工作，那里没有问题.但是，当我包含变体头文件时，会出现此错误:
Any works fine, no problems there. However, when I include the variant header file, I get this error:
/usr/include/c++/7/bits/c++17_warning.h:32: error: #error This file requires compiler and library support for the ISO C++ 2017 standard. This support must be enabled with the -std=c++17 or -std=gnu++17 compiler options.
#error此文件需要编译器和库支持\ ^ ~~~~
#error This file requires compiler and library support \ ^~~~~
我已经尝试了项目文件中的各种操作，这是完整列表:
I have tried a variety of things in the project file, here is the full list:
CONFIG += c++17
&
CONFIG += c++1z
&
QMAKE_CXXFLAGS += -std=c++17
&
QMAKE_CXXFLAGS += -std=c++1z
&
CONFIG += c++17
QMAKE_CXXFLAGS += -std=c++17
&
CONFIG += c++1z
QMAKE_CXXFLAGS += -std=c++1z
&
CONFIG += c++11
CONFIG += c++14
CONFIG += c++17
那是我能想到的黑暗中的每一次刺伤.我想念什么?为什么experimental::any在变体没有编译时会编译?
That's every stab in the dark I could think of. What am I missing? And why does experimental::any compile when variant doesn't?
我知道我不应该以此方式同时使用CONFIG += c++xx和QMAKE_CXXFLAGS，但是我认为我会尝试一下，因为其他方法都无效.为了获得加分，我还想知道，当我已经为17进行配置时，我应该添加针对14和11的CONFIG调用吗?
I know I shouldn't use CONFIG += c++xx and QMAKE_CXXFLAGS together in this way, but I thought I'd give it a go as nothing else works. For bonus points, I'm also wondering, should I add the CONFIG calls for 14 and 11 when I already CONFIG for 17?
这是编译器的输出，其中大部分文件名都被清除了:
Here is the compiler output with most of my filenames scrubbed out:
18:04:10: Running steps for project AIQt...
18:04:10: Configuration unchanged, skipping qmake step.
18:04:10: Starting: "/usr/bin/make"
/home/pete/Qt/5.9.1/gcc_64/bin/qmake -o Makefile ../AIQt/AIQt.pro -spec linux-g++ CONFIG+=debug CONFIG+=qml_debug
WARNING: Failure to find: ../src/stdafx.h
WARNING: Failure to find: ../src/Csound/csd.h
g++ -c -pipe -g -Wall -W -D_REENTRANT -fPIC -DQT_DEPRECATED_WARNINGS -DQT_QML_DEBUG -DQT_DATAVISUALIZATION_LIB -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I../AIQt -I. -I../src -I../src/AIBase -I../src/Maths -I../src/Random -isystem /usr/local/include/csound -I../../../../Qt/5.9.1/gcc_64/include -I../../../../Qt/5.9.1/gcc_64/include/QtDataVisualization -I../../../../Qt/5.9.1/gcc_64/include/QtWidgets -I../../../../Qt/5.9.1/gcc_64/include/QtGui -I../../../../Qt/5.9.1/gcc_64/include/QtCore -I. -isystem /usr/include/libdrm -I. -I../../../../Qt/5.9.1/gcc_64/mkspecs/linux-g++ -o main.o ../AIQt/main.cpp
In file included from /usr/include/c++/7/variant:35:0,
from ..###,
from ..###,
from ..###,
from ..###,
from ..###,
from ..###,
from ..###,
from ..###:
/usr/include/c++/7/bits/c++17_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2017 standard. This support must be enabled with the -std=c++17 or -std=gnu++17 compiler options.
#error This file requires compiler and library support \
^~~~~
In file included from ..###,
from ..###
from ..###,
from ..###,
from ..###,
from ..###,
from ..###:
../src/AIBase/Geno.h:70:18: error: ‘variant’ in namespace ‘std’ does not name a type
std::variant m_valueVariant;
^~~~~~~
In file included from ..###,
from ..###,
from ..###,
from ..###,
from ..###,
from ..###:
../src/AIBase/Pheno.h:22:13: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
const double getGenoValue(size_t genoIndex) const;
^~~~~
../src/AIBase/Pheno.h:24:13: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
const UserRating getRating() const;
^~~~~
In file included from ..###,
from ..###:
../AIRadioQt/GraphDialog.h:16:15: warning: declaration ‘struct ar::ai::ClusterList’ does not declare anything
class ar::ai::ClusterList;
^~~~~~~~~~~
make: *** [main.o] Error 1
18:04:13: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project AIQt (kit: Qt 5.9.1 GCC 64bit)
The kit Qt 5.9.1 GCC 64bit has configuration issues which might be the root cause for this problem.
When executing step "Make"
18:04:13: Elapsed time: 00:03.
答案:
正如nwp所说，我只需要清理并重建.
As mentioned by nwp, I just had to clean it and rebuild.
另一位发帖人也评论说，似乎尚不支持CONFIG += c++17，因此有必要使用QMAKE_CXXFLAGS += -std=c++17.不过，他很快删除了他的评论，所以我个人感谢他为我检查文档的努力.
Another poster also commented that CONFIG += c++17 doesn't appear to be supported yet, so it is necessary to use QMAKE_CXXFLAGS += -std=c++17. He quickly deleted his comment though, so I am unable to thank him personally for going to the effort of checking the docs for me.
推荐答案
CONFIG += c++17可以与Qt 5.12及更高版本一起使用.
CONFIG += c++17 can be used with Qt 5.12 and later.
对于Qt 5.11及更早版本，它不是公认的QMake标记，那么您就必须弄脏手.
For Qt 5.11 and earlier, it is not a recognized QMake flag and you have to get your hands a bit dirty.
添加QMAKE_CXXFLAGS += -std=c++17可以完成GCC和铛;对于MSVC，您可能可能需要指定 /std:c++17或/std:c++latest.
Adding QMAKE_CXXFLAGS += -std=c++17 does the job for GCC & Clang; for MSVC you will probably need to specify /std:c++17 or /std:c++latest.
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