Question

我会直接去MCVE：

#include <sstream>

struct A
{
    inline static std::stringstream ss;
};

GCC 7.2和7.1 refuse to compile出现以下错误：

error: no matching function for call to 'std::__cxx11::basic_stringstream::basic_stringstream()'
     inline static std::stringstream ss;
                                     ^~
In file included from blah:1:0:
/opt/compiler-explorer/gcc-7.2.0/include/c++/7.2.0/sstream:723:7: note: candidate: std::__cxx11::basic_stringstream::basic_stringstream(std::__cxx11::basic_stringstream&&) [with _CharT = char; _Traits = std::char_traits; _Alloc = std::allocator]
       basic_stringstream(basic_stringstream&& __rhs)
       ^~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-7.2.0/include/c++/7.2.0/sstream:723:7: note:   candidate expects 1 argument, 0 provided

您可以在没有任何标记的情况下重现该标记，也可以使用-std=c++17重现。

Clang 5.0编译它没有任何问题。

其他类（例如std::string）可以inline static没有问题。

使其成为非内联静态可以消除错误。

不是GCC的错误，还是我错过了什么？

Answer 1

错误。减少到：

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [self.view addObserver:self forKeyPath:@"bounds" options:NSKeyValueObservingOptionNew context:nil];

    if (!_viewFirstAppeared) {
        _viewFirstAppeared = YES;

        void(^applyViews)(void) = ^{
            [self.centerController.view removeFromSuperview];
            [self.centerView addSubview:self.centerController.view];

            [self doForControllers:^(UIViewController* controller, IIViewDeckSide side) {
                [controller.view removeFromSuperview];
                [self.referenceView insertSubview:controller.view belowSubview:self.slidingControllerView];
            }];

            [self setSlidingFrameForOffset:_offset forOrientation:_offsetOrientation];
             self.slidingControllerView.hidden = NO;

             self.centerView.frame = self.centerViewBounds;
             self.centerController.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
             self.centerController.view.frame = self.centerView.bounds;
            [self doForControllers:^(UIViewController* controller, IIViewDeckSide side) {
                controller.view.frame = self.sideViewBounds;
                controller.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
            }];

            [self applyShadowToSlidingViewAnimated:NO];
        };

        if ([self setSlidingAndReferenceViews]) {
            applyViews();
            applyViews = nil;
        }

        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.001 * NSEC_PER_SEC), dispatch_get_main_queue(), ^(void){
            if (applyViews) applyViews();
            [self setSlidingFrameForOffset:_offset forOrientation:_offsetOrientation];
            [self hideAppropriateSideViews];
        });

        [self addPanners];

        if ([self isSideClosed:IIViewDeckLeftSide] && [self isSideClosed:IIViewDeckRightSide] && [self isSideClosed:IIViewDeckTopSide] && [self isSideClosed:IIViewDeckBottomSide])
            [self centerViewVisible];
        else
            [self centerViewHidden];
        }
    else if (_willAppearShouldArrangeViewsAfterRotation != UIDeviceOrientationUnknown) {
        for (NSString* key in [self.view.layer animationKeys]) {
            [self.view.layer animationForKey:key].duration);
        }

        [self willRotateToInterfaceOrientation:self.interfaceOrientation duration:0];
        [self willAnimateRotationToInterfaceOrientation:self.interfaceOrientation duration:0];
        [self didRotateFromInterfaceOrientation:_willAppearShouldArrangeViewsAfterRotation];
    }

    [self.centerController viewWillAppear:animated];
    [self transitionAppearanceFrom:0 to:1 animated:animated];
    _viewAppeared = 1;
}

GCC初始化处理代码中的某些地方错误地将其视为复制初始化上下文，忽略了显式默认构造函数。

为什么GCC不允许我创建`inline static std :: stringstream`？

1 个答案: