C++26 标准引入新的调试头文件

C++26 标准通过 P2546R5 和 P2810R4 提案正式引入了 <debugging> 头文件，为 C++ 开发者提供了三个标准化的调试函数1。这一新增功能旨在解决多个 C++ 项目各自实现调试断点的重复问题1。

新增的三个调试函数分别为：std::breakpoint() 用于触发无条件断点，在 x86 平台上通常编译为单个 int3 指令1；std::is_debugger_present() 用于检测调试器是否已附加到进程，其返回结果不被缓存1；std::breakpoint_if_debugging() 则在调试器附加时触发断点，否则无任何操作1。

这三个函数均被定义为 noexcept 和 freestanding，不支持 constexpr 特性1。其中 std::is_debugger_present() 可被替换，采用与 operator new 和 operator delete 类似的机制1。该提案由 Rene Ferdinand Rivera Morell 提出1。

C++26 will introduce a new <debugging> header that provides standardized debugging utilities across the language standard 1. The addition, enabled through proposals P2546R5 and P2810R4, includes three core functions designed to address the fragmented landscape of debugging implementations currently scattered across different C++ projects 1.

The header defines std::breakpoint(), which triggers an unconditional breakpoint and typically compiles to a single int3 instruction on x86 platforms 1. Complementing this is std::is_debugger_present(), a function that detects whether a debugger is currently attached to the process; notably, its result is not cached and must be queried each time it is called 1. A third convenience function, std::breakpoint_if_debugging(), combines both capabilities by triggering a breakpoint only when a debugger is detected, otherwise performing no operation 1.

All three functions are designated as noexcept and freestanding, making them available in restricted compilation environments 1. Neither supports compile-time evaluation through constexpr 1. Notably, std::is_debugger_present() is classified as replaceable, following the same customization model as operator new and operator delete, allowing implementations or users to substitute their own versions 1. The proposal was authored by Rene Ferdinand Rivera Morell 1.