Is casting of infinity to integer undefined?

Question

Is the casting of infinity (represented by float) to an integer an undefined behavior?

The standard says:

4.10 Floating-integral conversions<

Answer 1

I'm trying to understand why std::numeric_limits::infinity() and static_cast(std::numeric_limits::infinity() ) have different results.

The standard says: 18.3.2.4

static constexpr T infinity() noexcept;

47 Representation of positive infinity, if available. [216]

48 Meaningful for all specializations for which has_infinity != false. Required in specializations for which is_iec559 != false.

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According to 18.3.2.7/1 [numeric.special]

1 All members shall be provided for all specializations. However, many values are only required to be meaningful under certain conditions (for example, epsilon() is only meaningful if is_integer is false). Any value that is not “meaningful” shall be set to 0 or false.