1、cmake .. PS D:\work\modern_cpp_work\ModernCpp\codes\std\expected\01\build> cmake .. -- Building for: Visual Studio 17 2022 -- Selecting Windows SDK version 10.0.19041.0 to target Windows 10.0.22621. -- The C compiler identification is MSVC 19.38.33130.0 -- The CXX compiler identi...
202211L(C++23)Monadic functions forstd::expected Example Run this code #include <cmath>#include <expected>#include <iomanip>#include <iostream>#include <string_view>enumclassparse_error{invalid_input, overflow};autoparse_number(std::string_view&str)->std::expected<double, parse_error>{constch...
module; #include <expected> export module B; import A; export std::expected<int, int> bar() { return foo(); } example.cpp import B; int main() { if (auto r = bar()) { return *r; } else { return r.error(); } } I get the following error: [4/6] ...
而最接近的std::visit又缺少编译器的优化支持,所以在c++17中std::variant并不好用,跟Rust和函数式语言中出神入化的Sum Type还相去甚远,但是已经有许多围绕std::variant的提案被提交给c++委员会探讨,包括模式匹配,std::expected等等。
store(1, std::memory_order_release); return; } void Broker() { int expected = 1; while (!flag.compare_exchange_strong(expected, 2, std::memory_order_acq_rel)) { expected = 1; } }; void Consumer() { while (flag.load(std::memory_order_acquire) < 2); if (data[0] != 42) ...
#include <cassert>#include <expected>#include <iomanip>#include <iostream>#include <string>intmain(){usingnamespacestd::string_literals;std::expected<int,std::string>ex1=6;assert(*ex1==6);*ex1=9;assert(*ex1==9);// *ex1 = "error"s; // error, ex1 contains an expected value of typ...
to be undefined behaviour. In this implementation it causes an assertion failure. The implementation of assertions can be overridden by defining the macroTL_ASSERT(boolean_condition)before #including <tl/expected.hpp>; by default,assert(boolean_condition)from the<cassert>header is used. Note that ...
expected:期望值的地址,也是输入参数,表示要比较的值; val:新值,也是输入参数,表示期望值等于该值时需要替换的值; success:表示函数执行成功时内存序的类型,默认为memory_order_seq_cst; failure:表示函数执行失败时内存序的类型,默认为memory_order_seq_cst。 该函数的返回值为bool类型,表示操作是否成功。 注意,...
问错误C2039：“”binder2nd“”：不是“std”的成员-具有特征的编译器错误EN这样写可以正常打印getdata...
3.compare_exchange_weak/strong函数可以保证“比较-交换”的原子化。compare_exchange_weak可能失败,即此函数可能与expected值相等的情形下atomic的T值没有替换为disired(atomic值未变)且返回false,这可能发生在缺少单条CAS操作(“比较-交换”指令)的机器上,所以通常使用一个循环中。