Question

I have a problem that I can’t resolve. Let’s say I have this map definition:

map<string, int16_t> Registers;

but sometimes, I need to store an unsigned int16_t instead of a signed int16_t.
How can I do that?

Thanks.

Answer 1

You can either use a bigger fish type, like int32_t, or use a boost::variant.

An int32_t can store all the values that an int16_t or an uint16_t can, and it preserves the difference between, for example, 32768 and -32768 (assuming two’s complement). If you used some casting scheme with int16_t and uint16_t the difference between these would be lost as both would be stored as 0x8000. Telling values like 0x8000 apart would require out-of-band information, which if you have, you did not mention.

However, int32_t won’t preserve the difference between 32767 signed and 32767 unsigned. If that matters, then boost::variant can preserve that information.