Re: Same code and different result, Why?
K?r?at wrote:
I have a question about sequence points : Function entry points are
sequence points, so all parameters should be evaluated and all
related side-effects realized before entering the function body.
Let's consider a code fragment like this :
void f (int i)
{
printf ("%d", i);
}
int main ()
{
int i = 5;
f (i++);
return 0;
}
According to the sequence point definition ebove, i's value should be
incremented before entering body of f() but in my tests with VS 2008
it's value is 5 in the f() and it is incremented after f() returns.
Why?
Because you're not reading the variable that got incremented!
Try this and you will see that the side effects are definitely performed
before the function call:
int i = 5;
void f (int j)
{
printf ("%d %d", i, j);
}
int main ()
{
f (i++);
return 0;
}
"Ulrich Eckhardt" <eckhardt@satorlaser.com> wrote in message
news:iklau5-8s6.ln1@satorlaser.homedns.org...
Lorry Astra wrote:
x = x++ + y++;
You are modifying x twice between sequence points, once incrementing
and once assigning, making this implementation-defined or even
undefined behaviour. Just search the web for 'sequence point' in the
context of C or check the comp.lang.c FAQ, I think it's also
explained there. Uli
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