How will you find out if a stack grows up or down in a system?

Question

Possible Duplicates:
stack growth direction
Does stack grow upward or downward?

Hi all,

How would I find out if a machine’s stack grows up or down in memory in C. More importantly, which is better: a system in which the stack grows up or one in which a stack grows down ?

And will below logic work ???

void sub(int *a) 
{
int b;

if (&b > a) {
printf("Stack grows up.");
}
else  
{
printf("Stack grows down.");
}
}
main ()
{
int a;
sub(&a);
}

I mean this expression is valid in C

if (&b > a)

What do you mean by "which is better"? Is a yellow apple "better" or a red apple? — user541686, Mar 19 '11 at 09:01
Possible duplicate: http://stackoverflow.com/questions/3572610/stack-growth-direction — Saurabh Manchanda, Mar 19 '11 at 09:02
@Mehrdad which is better means i would like to know like when stack goes upward it throws stack overflow kind of problem and what happen stack goes down and cross some limit.. — Amit Singh Tomar, Mar 19 '11 at 09:29

score 6 · Answer 1 · answered Mar 19 '11 at 09:03

Stacks don't even have to exist in the first place, and when they do, they don't have to work in the way you expect. They can be created dynamically, for example, or they could just jump around in memory. Your question isn't really a pure "C" question, because it isn't portable.

However, assuming that stacks either grow up or grow down, then you can just check this by taking the address of a variable inside a caller function and also inside a callee, and checking to see which one is greater; it's straightforward.

How will you find out if a stack grows up or down in a system?

1 Answers1

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