Re: [avr-gcc-list] Should this code work? 4.1.1

[Francesco Sacchi]

Bob Paddock ha scritto:
> The "falls out" is the issue with me, as I see the {} as being "contained 
> within",
> the "}" was never crossed, so to me it was still the same {} block.  I could not
> find this "reinitialize" issue in my old K&R book?

The condition of the loop must me somehow checked. When you reach the 
"}", the execution crosses braces boundary and jumps to the check of for 
loop condition. If you write:

for (;;)
{
        ...
}

the condition is not well visible, as it has been omitted, but think if 
you write:

for (i = 0; i < 10; i++)
{
        ...
}

when the execution reaches the "}", jumps to:

i < 10

and if the condition is true the block is re-executed from the 
beginning. So variables declared inside the block die and reborn at 
every round.

You can see very well this behavior with a step-by-step debugger 
execution: when executing a loop, if you reach the block end, the 
execution jumps to the line containing the loop condition, crossing 
braces boundary.



--
_|/ Francesco Sacchi - Develer S.r.l., R&D dept.
 |\ http://www.develer.com/