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

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< cpp‎ | numeric‎ | math
 
 
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Defined in header <cmath>
(1)
float       fmax ( float x, float y );

double      fmax ( double x, double y );

long double fmax ( long double x, long double y );
(until C++23)
constexpr /*floating-point-type*/

            fmax ( /*floating-point-type*/ x,

                   /*floating-point-type*/ y );
(since C++23)
float       fmaxf( float x, float y );
(2) (since C++11)
(constexpr since C++23)
long double fmaxl( long double x, long double y );
(3) (since C++11)
(constexpr since C++23)
SIMD overload (since C++26)
Defined in header <simd>
template< class V0, class V1 >

constexpr /*math-common-simd-t*/<V0, V1>

            fmax ( const V0& v_x, const V1& v_y );
(S) (since C++26)
Additional overloads (since C++11)
Defined in header <cmath>
template< class Integer >
double      fmax ( Integer x, Integer y );
(A) (constexpr since C++23)
1-3) 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). The library provides overloads of std::fmax for all cv-unqualified floating-point types as the type of the parameters.(since C++23)
S) The SIMD overload performs an element-wise std::fmax on v_xand v_y.
(See math-common-simd-t for its definition.)
(since C++26)
A) Additional overloads are provided for all integer types, which are treated as double.
(since C++11)

Contents

[edit] Parameters

x, y - floating-point or integer values

[edit] 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.

[edit] 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.

[edit] 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.

The additional overloads are not required to be provided exactly as (A). They only need to be sufficient to ensure that for their first argument num1 and second argument num2:

  • If num1 or num2 has type long double, then std::fmax(num1, num2) has the same effect as std::fmax(static_cast<long double>(num1),
              static_cast<long double>(num2))    .
  • Otherwise, if num1 and/or num2 has type double or an integer type, then std::fmax(num1, num2) has the same effect as std::fmax(static_cast<double>(num1),
              static_cast<double>(num2))    .
  • Otherwise, if num1 or num2 has type float, then std::fmax(num1, num2) has the same effect as std::fmax(static_cast<float>(num1),
              static_cast<float>(num2))    .
(until C++23)

If num1 and num2 have arithmetic types, then std::fmax(num1, num2) has the same effect as std::fmax(static_cast</*common-floating-point-type*/>(num1),
          static_cast</*common-floating-point-type*/>(num2)), where /*common-floating-point-type*/ is the floating-point type with the greatest floating-point conversion rank and greatest floating-point conversion subrank between the types of num1 and num2, arguments of integer type are considered to have the same floating-point conversion rank as double.

If no such floating-point type with the greatest rank and subrank exists, then overload resolution does not result in a usable candidate from the overloads provided.

(since C++23)

[edit] Example

Run this code
#include <cmath>
#include <iostream>
 
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

[edit] See also

(C++11)
checks if the first floating-point argument is greater than the second
(function) [edit]
(C++11)(C++11)(C++11)
smaller of two floating point values
(function) [edit]
returns the greater of the given values
(function template) [edit]
returns the largest element in a range
(function template) [edit]
(C++11)
returns the smaller and larger of two elements
(function template) [edit]
returns the smallest and the largest elements in a range
(function template) [edit]
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