[ros-dev] Re: Compiler-independence for 64-bit integral constants

[Kohn Emil Dan]

How about avoiding the compiler suffix altogether and only cast the
constants to a (platform independent) typedef, something like
this:

#ifdef __GNUC__
typedef long long INT64;
#elif defined _MSC_VER
typedef __int64 INT64;
#else
#error Please define the INT64 typedef according to your platform
#endif

and then use something like

a = (INT64)0x1;

Or we could hide the cast behind a macro such as

#define ZZZ(x) ((INT64)(x))


(I have no idea what to put instead of ZZZ MAKE_INT64 or DEFINE_INT64).


I see several advantages to this scheme:

1) It can be used both for constants and other expressions

2) It does not care about literal suffixes (e.g. whether the ll suffix
means that the constant has a size of 64 bit or 128 bits). All we have to
do is to define the INT64 typedef appropriately. I doubt that the compiler
will generate a different code between

x = 0ll;

and

x = (long long)0;


What do you think?


								Emil