c/numeric/math/floor

@1-3@ Computes the largest integer value not greater than. @4@ Type-generic macro: If has type,  is called. Otherwise, if has integer type or the type,  is called. Otherwise, is called.

Return value
If no errors occur, the largest integer value not greater than, that is $⌊arg⌋$, is returned.

Error handling
Errors are reported as specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),
 * The current rounding mode has no effect.
 * If is ±∞, it is returned, unmodified
 * If is ±0, it is returned, unmodified
 * If arg is NaN, NaN is returned