On Tue, 10 Nov 2009 16:15:26 -0500, bearophile <bearophileh...@lycos.com>
wrote:
Yigal Chripun:
Regardless of usefulness (or good design) of such variables, this sounds
extremely dangerous. The compiler must not change semantics of the
program based on optimization. optimizing away such variables most
definitely alters the semantics.
Maybe you have misunderstood, or I have explained the things badly. So I
explain again.
I have seen that LDC (when it performs link-time optimization, that's
not done in all situations) keeps just one copy of constants inside the
binary even if such constants are present in more than one template
instance. In the situations where LTO is available I think this doesn't
cause problems.
Then I am half-seriously proposing a syntax like:
T foo(T)(T x) {
static static int y;
// ...
}
Where the y is now static to (shared among) all instances of the
templated function foo. This may be a little error-prone and maybe not
that useful, but again here the compiler doesn't change the semantics of
the program, because using a double static keyword the programmer has
stated such intention.
What's the advantage over:
static int y;
T foo(T)(T x) {
// ...
}
-Steve
