/C

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)

 isgreaterequal (C99) checks if the first floating-point argument is greater or equal than the second (function macro) C++ documentation for `islessequal`