| re: Evaluation order for nested function calls
"cheeser" <cheeser_1998@yahoo.com> wrote in message
news:%DPfb.7978$La.3766@fed1read02...[color=blue]
> Hello all,
>
> Consider nested function calls:
>
> foo1(
> foo2( foo3()),
>
> foo4(
> foo5(),
> foo6(foo7())
> ),
>
> foo8()
> );
>
> There are obvious dependencies here such as that foo3() must be called
> before foo2(). Other than the required dependencies of this ilk, is there
> any guarantee that these 8 function calls will be made in any particular
> order?[/color]
No.
[color=blue]
>
> The two (slightly different) orderings shown below meet the obvious
> dependencies just described. What I would like to know though is if they
> are *both* within the realm of Standard-conforming behavior.
>
> ORDER 1:
> foo7()
> foo8()
> foo3()
> foo5()
> foo2()
> foo6()
> foo4()
> foo1()
>
> ORDER 2:
> foo7()
> foo3()
> foo5()
> foo2()
> foo6()
> foo4()
> foo8()
> foo1()
>
> The obvious concern here is that the lack of a completly well-defined[/color]
order[color=blue]
> could cause the same program to behave differently under two different
> compilers.[/color]
Yes it can.
#include <iostream>
int foo(int i, int j)
{
return i - j;
}
int main()
{
int x = 0;
int y = 0;
std::cout << foo(x = 42, y = x);
return 0;
}
Output could be 42 or 0.
-Mike
| 
