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We know CPython promotes integers to long integers (which allow arbitrary-precision arithmetic) silently when the number gets bigger.
How can we detect overflow of int and long long in pure C?
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asked Apr 02 '19 07:04
Write a “C” function, int addOvf(int* result, int a, int b) If there is no overflow, the function places the resultant = sum a+b in “result” and returns 0. Otherwise it returns -1. The solution of casting to long and adding to find detecting the overflow is not allowed.
That is, if a <= INT_MAX / b, then the multiplication would overflow. Remember that when you divide both sides of the inequality by b , you must flip the inequality if b is negative.
In languages where integer overflow can occur, you can reduce its likelihood by using larger integer types, like Java's long or C's long long int. If you need to store something even bigger, there are libraries built to handle arbitrarily large numbers.
You cannot detect signed int overflow. You have to write your code to avoid it.
Signed int overflow is Undefined Behaviour and if it is present in your program, the program is invalid and the compiler is not required to generate any specific behaviour.
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