std::fetestexcept
来自 cppreference.cn
| 定义于头文件 <cfenv> |
||
| int fetestexcept( int excepts ); |
(C++11 起) | |
确定当前设置了哪些指定的浮点异常子集。参数 excepts 是 浮点异常宏 的按位或。
目录 |
[编辑] 参数
| excepts | - | 位掩码，列出要测试的异常标志 |
[编辑] 返回值
浮点异常宏的按位或，这些宏既包含在 excepts 中，又对应于当前设置的浮点异常。
[编辑] 示例
运行此代码
#include <cfenv> #include <cmath> #include <iostream> // #pragma STDC FENV_ACCESS ON volatile double zero = 0.0; // volatile not needed where FENV_ACCESS is supported volatile double one = 1.0; // volatile not needed where FENV_ACCESS is supported int main() { std::feclearexcept(FE_ALL_EXCEPT); std::cout << "1.0/0.0 = " << 1.0 / zero << '\n'; if (std::fetestexcept(FE_DIVBYZERO)) std::cout << "division by zero reported\n"; else std::cout << "division by zero not reported\n"; std::feclearexcept(FE_ALL_EXCEPT); std::cout << "1.0/10 = " << one / 10 << '\n'; if (std::fetestexcept(FE_INEXACT)) std::cout << "inexact result reported\n"; else std::cout << "inexact result not reported\n"; std::feclearexcept(FE_ALL_EXCEPT); std::cout << "sqrt(-1) = " << std::sqrt(-1) << '\n'; if (std::fetestexcept(FE_INVALID)) std::cout << "invalid result reported\n"; else std::cout << "invalid result not reported\n"; }
可能的输出
1.0/0.0 = inf division by zero reported 1.0/10 = 0.1 inexact result reported sqrt(-1) = -nan invalid result reported
[编辑] 参见
| (C++11) |
清除指定的浮点状态标志 (函数) |
| C 文档 关于 fetestexcept
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