std::fmax, std::fmaxf, std::fmaxl

Defined in header `<cmath>`
float fmax ( float x, float y );	(1)	(since C++11) (constexpr since C++23)
float fmaxf( float x, float y );	(2)	(since C++11) (constexpr since C++23)
double fmax ( double x, double y );	(3)	(since C++11) (constexpr since C++23)
long double fmax ( long double x, long double y );	(4)	(since C++11) (constexpr since C++23)
long double fmaxl( long double x, long double y );	(5)	(since C++11) (constexpr since C++23)
Promoted fmax ( Arithmetic1 x, Arithmetic2 y );	(6)	(since C++11) (constexpr since C++23)

1-5) Returns the larger of two floating point arguments, treating NaNs as missing data (between a NaN and a numeric value, the numeric value is chosen)

6) A set of overloads or a function template for all combinations of arguments of arithmetic type not covered by (1-5). If any argument has integral type, it is cast to double. If any other argument is long double, then the return type is long double, otherwise it is double.

Parameters

x, y

-

values of floating-point or integral types

Return value

If successful, returns the larger of two floating point values. The value returned is exact and does not depend on any rounding modes.

Error handling

This function is not subject to any of the error conditions specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

If one of the two arguments is NaN, the value of the other argument is returned
Only if both arguments are NaN, NaN is returned

Notes

This function is not required to be sensitive to the sign of zero, although some implementations additionally enforce that if one argument is +0 and the other is -0, then +0 is returned.

Example

Run this code

#include <iostream>
#include <cmath>
 
int main()
{
    std::cout << "fmax(2,1)    = " << std::fmax(2,1) << '\n'
              << "fmax(-Inf,0) = " << std::fmax(-INFINITY,0) << '\n'
              << "fmax(NaN,-1) = " << std::fmax(NAN,-1) << '\n';
}

Output:

fmax(2,1)    = 2
fmax(-Inf,0) = 0
fmax(NaN,-1) = -1

Compiler support
Freestanding and hosted
Language
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Technical specifications
Symbols index
External libraries

Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Floating-point environment (C++11)
Complex numbers
Numeric arrays
Pseudo-random number generation
Factor operations
gcd (C++17)
lcm (C++17)
Interpolations
midpoint (C++20)
lerp (C++20)
Generic numeric operations
iota (C++11)
ranges::iota (C++23)
accumulate
inner_product
adjacent_difference
partial_sum
reduce (C++17)
transform_reduce (C++17)
inclusive_scan (C++17)
exclusive_scan (C++17)
transform_inclusive_scan (C++17)
transform_exclusive_scan (C++17)
Bit operations
bit_cast (C++20)
byteswap (C++23)
has_single_bit (C++20)
bit_ceil (C++20)
bit_floor (C++20)
bit_width (C++20)
rotl (C++20)
rotr (C++20)
countl_zero (C++20)
countl_one (C++20)
countr_zero (C++20)
countr_one (C++20)
popcount (C++20)
endian (C++20)

isgreater (C++11)	checks if the first floating-point argument is greater than the second (function)
fminfminffminl (C++11)(C++11)(C++11)	smaller of two floating point values (function)
max	returns the greater of the given values (function template)
max_element	returns the largest element in a range (function template)
minmax (C++11)	returns the smaller and larger of two elements (function template)
minmax_element (C++11)	returns the smallest and the largest elements in a range (function template)