前情提要:The History of constexpr in C++! (Part One) 2015-2016:模板的语法糖 在C++ 中支持 全特化 (full specialization) 的模板很多,但是支持 偏特化 (partial specialization) 的模板并不多,事实上其实只有类模板 (class template) 和变量模板 (variable template) 两种支持,而变量模板其实可以看做类模板...
The evaluation of non-constexpris significantly slower. It is likely due to a bug or limitation in the optimizer. However, this issue seems to have been resolved in G++ 8.1 or newer versions, as there is no difference in compilation times. Solution 2: The fact that the compilation time is...
There are several improvements in C++11 that promise to allow programs written using C++11 to run faster than ever before. One of those improvements, generalized constant expressions, allows programs to take advantage of compile-time computation. If you're familiar with template metaprogramming, ...
100);static_assert(c==200);constexprautoval=10;static_assert(sum(val,val)==2*val);inta=10;intb=sum_c(a,10);// fine with constexpr function// int d = sum(a, 10); // error! the value of 'a' is// not usable in a constant expression}...
Exception handling in C++ Assertion and user-supplied messages Modules Templates Event handling Microsoft-specific modifiers Compiler COM support Microsoft extensions Nonstandard behavior Compiler limits C/C++ preprocessor reference C++ standard library reference ...
Constexpr and templates results in C3615 Closed - Fixed14 0Votes VJVuk Jovanovic [MSFT] -Reported Aug 14, 2019 5:28 PM Here is the link to minimal repro:https://gcc.godbolt.org/z/HMpy_- If you comment out any of the lines that define USE_TEMPLATE, USE...
@文心快码‘constexpr’ needed for in-class initialization of static data member ‘con 文心快码 在C++中,对于非整型(如double)的静态数据成员,在类内进行初始化时需要使用‘constexpr’关键字。 在C++中,静态数据成员可以在类内声明,但必须在类外定义(除非它们是整型常量或使用了constexpr)。这是因为静态数据...
1 constexpr说明符只能应用于变量或变量模板的定义、函数或函数模板的声明或文字类型的静态数据成员的声明...
In the sample below, the initialized supplied to the constexpr constructor is a constant, so Update 1 can statically initialize it. Note that the type has a destructor, which makes the type a non-literal type. Copy extern "C" int puts(const char*); Copy struct NonLiteralType { Copy ...
考虑使用CMake在构建时生成文件，记录开关值，然后在需要判断的地方使用if constexpr。这样，编译器会识别无执行分支，避免编译，实现代码剔除。在CMakeLists.txt中，需添加构建参数，将选项导入文件中，并进行替换。使用宏定义实现，也可以直接书写，如在options.h.in文件中按CMake规范操作。在main.cpp...