El 13/3/2008, a las 0:39, Junio C Hamano escribió:
Ah,...
But C language rules haven't changed in such a way that it
guarantees B to
be evaluated before A when you write "A >= B", have it?
So at least I think you would need something like this if you go that
route:
if (strcmp(value, "now")) {
unsigned long now = approxidate("now");
if (approxidate(value) >= now)
return error("Invalid %s: '%s'", var, value);
...
}
Are you sure that that alternative provides any guarantees about
evaluation order either? (I'm not a compiler expert, nor am I
consulting a copy of the standard; but I don't think it does.)
In order to enforce evaluation in the required order I think it might
have to be something like this:
if (strcmp(value, "now")) {
unsigned long now;
if ((now = approxidate("now")) &&
approxidate(value) >= now)
return error("Invalid %s: '%s'", var, value);
...
}
ie. the && operator guarantees left to right evaluation order, and
since approxidate always returns a non-zero ulong the second
expression (after the &&) will always be evaluated.
Cheers,
Wincent
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