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std::signbit(3) C++ Standard Libary std::signbit(3) NAME std::signbit - std::signbit Synopsis Defined in header <cmath> bool signbit( float arg ); (1) (since C++11) (constexpr since C++23) bool signbit( double arg ); (2) (since C++11) (constexpr since C++23) bool signbit( long double arg ); (3) (since C++11) (constexpr since C++23) bool signbit( IntegralType arg ); (4) (since C++11) (constexpr since C++23) 1-3) Determines if the given floating point number arg is negative. 4) A set of overloads or a function template accepting the arg argu- ment of any integral type. Equivalent to (2) (the argument is cast to double). Parameters arg - floating point value Return value true if arg is negative, false otherwise Notes This function detects the sign bit of zeroes, infinities, and NaNs. Along with std::copysign, std::signbit is one of the only two portable ways to examine the sign of a NaN. Example // Run this code #include <iostream> #include <cmath> int main() { std::cout << std::boolalpha << "signbit(+0.0) = " << std::signbit(+0.0) << '\n' << "signbit(-0.0) = " << std::signbit(-0.0) << '\n'; } Output: signbit(+0.0) = false signbit(-0.0) = true See also abs(float) fabs fabsf absolute value of a floating point value (\(\small{|x|}\)|x|) fabsl (function) (C++11) (C++11) copysign copysignf copysignl copies the sign of a floating point value (C++11) (function) (C++11) (C++11) http://cppreference.com 2022.07.31 std::signbit(3)
NAME | Synopsis | Parameters | Return value | Notes | Example | Output: | See also
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