std::fetestexcept
来自cppreference.com
| 定义于头文件 <cfenv>
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| int fetestexcept( int excepts ); |
(C++11 起) | |
确定当前设定了哪个浮点异常的指定子集。参数 excepts 是浮点异常宏的逐位或。
参数
| excepts | - | 列出要测试的异常标志的位掩码 |
返回值
包含于 excepts 而且对应于当前设置的浮点异常中的浮点异常宏的逐位或。
示例
运行此代码
#include <iostream> #include <cfenv> #include <cmath> #pragma STDC FENV_ACCESS ON volatile double zero = 0.0; // 支持 FENV_ACCESS 处不需要 volatile volatile double one = 1.0; // 支持 FENV_ACCESS 处不需要 volatile 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 << "divsion 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"; } }
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
参阅
| (C++11) |
清除指定的浮点状态标志 (函数) |
