Why UuidFromString function requests non-const pointer to unsigned char?

Question

I have no idea why UuidFromString function requered non-const pointer to unsigned char. Why not const char* instead?

My thoughts that there is no need to data modification pointed by the first argument.

Answer 1

UuidFromString was designed for COM/DCOM.

The unsigned char is to prevent the need to check for negative char values (the default char is signed , meaning the values ranged [-128, 127] - since this string is supposed to be ANSI characters, it is a cheap way to avoid having a < 0 conditional check).

Its sister function ( UuidToString ) does take a const input parameter. I do not see a reason in the documentation as to why UuidFromString does not as well, but it is likely an oversight that was never addressed.