[amibroker] barcount and selected value, _trace and printf disagreement

[LongJack]

the code below gives an out of range error while I dont think it should.


I just want to access value of an array after the selected bar, to plot a 
forecast.
I tried with or without var required and I always get the same error, even if 
start<barcount( at least from what I can read in the interpretation window).
But if I trace it I get that start=barcount,which explain the error.
How can it be?


SetBarsRequired( -2, -2); 
bi=BarIndex();
        Plot(C,"C",colorBlue);
        start=SelectedValue(bi)-bi[0];
        printf("\n selected bi="+SelectedValue(bi));
        printf("\n bi[0]="+bi[0]);
        printf("\n start=selected bi-bi[0]="+start);
        printf("\n barcount"+BarCount);
        printf("\n start+1="+(start+1));
        printf("\n c[start]="+C[start]);
        

        _TRACE("\n selected bi="+SelectedValue(bi));
        _TRACE("\n bi[0]="+bi[0]);
        _TRACE("\n start=selected bi-bi[0]="+start);
        _TRACE("\n barcount"+BarCount);
        _TRACE("\n start+1="+(start+1));
        _TRACE("\n c[start]="+C[start]);
        _TRACE("\n c[start+1]="+C[start+1]);
        

        _TRACE("\n c[start+1]="+C[start+1]);
        printf("\n c[start+1]="+C[start+1]);

Regards
Ly