Subj : Re: Any help on why?
To   : borland.public.cpp.borlandcpp
From : maeder
Date : Wed Jul 07 2004 08:01 pm

Bob Gonder <notbg@notmindspring.invalid> writes:

> Thomas Maeder [TeamB] wrote:
>
>>Bob Gonder  writes:
>>
>>> Poster could have used %lX for float or double as %X is int, whatever
>>> size that is (target dependant)..
>>
>>Certainly not.
>
> Certainly not what? dependant? Ok, but I thought in the olden days
> floats were 4 bytes, doubles, double that (hence the distinction).

X and lX are for integral values. Using them for something else is an even
uglier hack than using the *printf() machinery at all.

To peek at the internals of, say, a double, the portable way is to
treat it as an array of unsigned char, as in

double d(3.11415);
unsigned char const *const begin(reinterpret_cast<unsigned char *>(&d));
unsigned char const *const end(begin + sizeof d);
for (unsigned char const *c = begin; c!=end; ++c)
  printf("%u ",static_cast<unsigned int>(*c));

The result of this snippet is not portable, but the approach looks very
portable to me.

.