On Sun, 2005-08-07 at 15:57 +0200, Thomas Petazzoni wrote:
> Hi,
>
> Bob Smith a écrit :
>
> > Why is that ? I googled up reasons like minimizing return points,
> > but is that it ?
>
> Most of the time, 'goto' is used to minimize code duplication in error
> handling.
>
> Without 'goto':
>
> int myfunc (void)
> {
> ret = dosomething1();
> if (ret < 0)
> return ret;
>
> ret = dosomething2();
> if (ret < 0)
> {
> undosomething1();
> return ret;
> }
>
> ret = dosomething3();
> if (ret < 0)
> {
> undosomething2();
> undosomething1();
> return ret;
> }
>
> ret = dosomething4();
> if (ret < 0)
> {
> undosomething3();
> undosomething2();
> undosomething1();
> return ret;
> }
> return 0;
> }
>
> With 'goto':
>
> int myfunc(void)
> {
> ret = dosomething1()
> if (ret < 0)
> goto ret_dosomething1;
>
> ret = dosomething2()
> if (ret < 0)
> goto ret_dosomething2;
>
> ret = dosomething3()
> if (ret < 0)
> goto ret_dosomething3;
>
> ret = dosomething4()
> if (ret < 0)
> goto ret_dosomething4;
>
> ret_dosomething4:
> undosomething3();
> ret_dosomething3:
> undosomething2();
> ret_dosomething2:
> undosomething1();
> ret_dosomething1:
> return ret;
> }
With 'if':
int myfunc(void)
{
ret = dosomething1()
if (ret >= 0) {
ret = dosomething2()
if (ret >= 0) {
ret = dosomething3()
if (ret >= 0) {
ret = dosomething4()
if (ret >= 0) {
...
}
}
undosomething3();
}
undosomething2();
}
undosomething1();
return ret;
}
Now remember that the kernel has 8 spaces indentation, not 3 as above.
Not that better, especially if your label names are quite descriptive.
Bernd
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