意味着case 2的流程也是需要跳转可以直接运行下去的,没有跳转处理器也就不需要清空流水线(此处简化理论,不涉及到处理器内部分支预测逻辑),case 2相对于case 1还是更加快速的流程,[[likely]]属性发挥了它应有的作用。
Linux内核编程时常用的likely()和unlikely()底层调用的likely_notrace()、unlikely_notrace()就是基于 __builtin_expect(EXP,C)实现的。 #define likely_notrace(x) __builtin_expect(!!(x), 1) #define unlikely_notrace(x) __builtin_expect(!!(x), 0) 若代码中出现分支,则即可能中断流水线,我们...
#define __printf(a, b) __attribute__((format(printf, a, b))) #define __scanf(a, b) __attribute__((format(scanf, a, b))) #define noinline __attribute__((noinline)) #define __attribute_const__ __attribute__((__const__)) #define __maybe_unused __attribute__((unused)) #...
t1_assert是宏名,expr是参数名,后面的都是宏函数定义的函数体。void是函数返回值类型,后面的是一个3元表达式,LIKELY(expr)函数的返回值为真时,宏函数的返回值是0;LIKELY(expr)函数的返回值为假时,宏函数的返回值是函数(VG_(assert_fail) (False, #expr, __FILE__, __LINE__, __PRETTY_FUNCTION__,""...
CFileStatus 結構的大小已變更:m_attribute 成員已從 BYTE 變更為 DWORD (以符合 GetFileAttributes 傳回的值)。CRichEditCtrl 和CRichEditView 會在Unicode 組建中使用 MSFTEDIT_CLASS (RichEdit 4.1 控制) 而非 RICHEDIT_CLASS (RichEdit 3.0 控制)。
P0479R5 [[likely]] and [[unlikely]] attributes VS 2019 16.6 20 P0692R1 Relaxing access checking on specializations VS 2019 16.6 14 P0732R2 Class types in non-type template parameters VS 2019 16.6 20 P1139R2 Address wording issues related to ISO 10646 VS 2019 16.6 14 ...
已更改 CFileStatus 结构大小:m_attribute 成员从 BYTE 更改为 DWORD(以匹配从 GetFileAttributes 返回的值)。在Unicode 版本中,CRichEditCtrl 和CRichEditView 使用MSFTEDIT_CLASS(RichEdit 4.1 控件),而不是使用 RICHEDIT_CLASS(RichEdit 3.0 控件)。删除了 AFX_GLOBAL_DATA::IsWindowsThemingDrawParentBackground,...
If you know which fields of a particular type are likely to contain duplicate strings, you can apply the string interning formatter to just those fields so the deserializer only pays for the interned string check where it matters most. Note that this technique requires a [MessagePackObject] or...
then each member of the array will also be 32-byte aligned. To create an array whose base is properly aligned, use_aligned_malloc, or write your own allocator. Note that normal allocators, such asmalloc, C++operator new, and the Win32 allocators return memory that will most likely not ...
Under /std:c++20 or /std:c++latest, the overloads make these insertions ill-formed, instead of behaving in what is likely an unintended manner. The compiler raises error C2280 when one is found. You can define the "escape hatch" macro _HAS_STREAM_INSERTION_OPERATORS_DELETED_IN_CXX20 to...