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islessequal

Defined in header `<math.h>`
#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 <stdio.h>
#include <math.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

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)