Re: How expensive are exceptions?
On Jun 26, 9:47 pm, "Sergey P. Derevyago" <non-exist...@iobox.com>
wrote:
fraca...@caesar.de wrote:
I have just read the section you were referring to, and did not find
anything which would imply that you should use both exceptions and
return values for error propagation.
Have you found the idea that return values are now obsolete?
As I have given an example on where and how to use them, I obviously
have neither found such a statement nor implied it in my post.
But not being obsoleted, doesn't mean you have to use return codes
when another error handling mechanism is already in place.
So to stay with your example and give a fair comparison, your code
should look like this, when using exceptions:
No, it should not.
Care to elaborate why? Both have the same semantic. The return value
in your example carries no other information than if the function
worked correctly. The same information is impicitly given when using
exceptions:
if the function returns, it worked.
So yes, in this case return codes get obsoleted by exceptions in this
case.
So what about this two examples, where the return values stay, because
they are needed for other reasons.
Without EH (assuming all *_ERROR constants are defined):
void f()
{
if (g1() == G1_ERROR) {
// check the error stack
}
}
int g1()
{
int gn = gN();
if (gn == GN_ERROR) return G1_ERROR;
return gn;
}
int gN()
{
int h = h();
if (h == H_ERROR) return GN_ERROR;
return h;
}
int h()
{
if (something_wrong) {
// push the error object to the error stack
return H_ERROR
}
return 42;
}
With EH:
void f()
{
try { g1(); }
catch (error& e) {
// do something about it.
}
}
int g1()
{
return gN();
}
int gN()
{
return h();
}
int h()
{
if (something_wrong) {
throw error(/* */);
}
return 42;
}
If you find this examples unfair, please explain why.
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