c - What happens when evaluating `int x = -2147483648`?

Question

What happens when evaluating

int x = -2147483648

?

1. When evaluating -2147483648, 2147483648 is a integer constant which has long type not int, so the result -2147483648 of evaluating -2147483648 is of type long, not int.

2. When evaluating the assignment "int x = ...", the RHS is value -2147483648 of long type, which is in the range of x's type int. Will value -2147483648 be implicitly converted from long to int, and the conversion keep the value -2147483648 unchanged?

Thanks.

Answer 1

Your analysis in this question is right. Because the value is in the range of int and is converted to int as part of the initialization (note: the same would happen for assignment), everything works as intended.

As for the hidden part of your question you didn't ask, since it keeps getting closed as a duplicate, this does not mean you can define INT_MIN as -2147483648. The magic is in the = (as assignment operator or a token in the initialization construct). In contexts where it's not being used, there are all sorts of ways that -2147483648 having type long or long long rather than int breaks semantic requirements on INT_MIN. For example:

• (INT_MIN < 0U) == 0 (because both operands are promoted to unsigned), but
• (-2147483648 < 0U) == 1 (because both operands are promoted to long or long long).