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islessequal - cppreference.com

From cppreference.com

#define islessequal(x, y) /* implementation defined */

 (since C99)

Determines if the floating-point number x is less than or equal to the floating-point number y, without setting floating-point exceptions.

Parameters

x - floating-point value
y - floating-point value

Return value

Nonzero integral value if x <= y, 0 otherwise.

Notes

The built-in operator<= for floating-point numbers may raise FE_INVALID if one or both of the arguments is NaN. This function is a "quiet" version of operator<=.

Example

#include <math.h>
#include <stdio.h>
 
int main(void)
{
    printf("islessequal(2.0,1.0)      = %d\n", islessequal(2.0, 1.0));
    printf("islessequal(1.0,2.0)      = %d\n", islessequal(1.0, 2.0));
    printf("islessequal(1.0,1.0)      = %d\n", islessequal(1.0, 1.0));
    printf("islessequal(INFINITY,1.0) = %d\n", islessequal(INFINITY, 1.0));
    printf("islessequal(1.0,NAN)      = %d\n", islessequal(1.0, NAN));
 
    return 0;
}

Possible output: 

islessequal(2.0,1.0)      = 0
islessequal(1.0,2.0)      = 1
islessequal(1.0,1.0)      = 1
islessequal(INFINITY,1.0) = 0
islessequal(1.0,NAN)      = 0

References

  • C23 standard (ISO/IEC 9899:2024):
  • 7.12.14.4 The islessequal macro (p: TBD)
  • F.10.11 Comparison macros (p: TBD)
  • C17 standard (ISO/IEC 9899:2018):
  • 7.12.14.4 The islessequal macro (p: TBD)
  • F.10.11 Comparison macros (p: TBD)
  • C11 standard (ISO/IEC 9899:2011):
  • 7.12.14.4 The islessequal macro (p: 260)
  • F.10.11 Comparison macros (p: 531)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.12.14.4 The islessequal macro (p: 241)

See also