How to limit the size of variable types, such as long int in a 64-bit system?

Question

So, long int on a 32-bit system is 32 bits, and on a 64-bit system - 64 bits. Now I am writing code on a 32-bit system without worrying about overflow. If I run the same code on a 64-bit system, all my long variables will unnecessarily take up twice as much memory, which is a waste. So, how to limit the size of a variable in a 64-bit system.

For example, I have a variable long long int Count. Now Count can contain a maximum of 63 bits in my design. If I run the same code on a 64-bit system, Count will be 128 bits, but according to the logic, the remaining 64 bits will be wasted. So, I want to make sure that the graph accepts only the 64-bit version on a 64-bit system.

Answer 1

So, long int on a 32-bit system is 32 bits, and on a 64-bit system 64 bits.

Not necessary. They can be 64 bits. Or they can be 32 bits.

So, how to limit the size of a variable in a 64-bit system.

Instead of using primitive default types in C, such as long, you should use int32_tfrom stdint.h. In contrast long, it is fully portable and has a deterministic size.

Answer 2

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