VB simple stuff...

ashirazi · 10-17-2004, 12:02 PM

Hey,

I'm not an expert in VB but can someone tell me what does the second line do?

Code:

 On Error Resume Next

I would also like to know about the built in error checking i.e. what does Err5 and Err6 checks for.

Code:

For i = 1 To smodules 
On Error Resume Next
kl(i, 1) = ks(i, 1) * Exp(-(-p(i, 0) / b(i, 1)) ^ cc(i, 1)) 
ku(i, 1) = ks(i, 1) * Exp(-(-p(i, 1) / b(i, 1)) ^ cc(i, 1)) 'weibull function for upper half of element i
If Err = 5 Then
    nodefailure = i
    nodetype = "lateral shoot"
    Exit Do
End If
nn = (-p(i, 1) / b(i, 1)) ^ cc(i, 1) 'n value for upper half in preparation for pgamma function
aa = 1 / cc(i, 1) 'assigns a value for incomplete gamma function
pgamma aa, nn 'calls function pgamma
If Err = 6 Then
    nodefailure = i
    nodetype = "lateral shoot"
    Exit Do
End If
phiu = (1 - gammp) * gamma * ks(i, 1) * b(i, 1) / cc(i, 1) 'phi for upper half
nn = (-p(i, 0) / b(i, 1)) ^ cc(i, 1) 'n value for lower half
pgamma aa, nn 'calls pgamma again with lower half n value
If Err = 6 Then
    nodefailure = i
    nodetype = "lateral shoot"
    Exit Do
End If
phil = (1 - gammp) * gamma * ks(i, 1) * b(i, 1) / cc(i, 1) 'phi for lower half
jl(i, 1) = cf(i, 1) * (phil - phiu) 'flux of element i--CF converts conductivity to conductance
Next i

Thanks
raven

acid_kewpie · 10-17-2004, 12:04 PM

on error resume next is VB's abissmal attempt at fault recovery. if it hits somesthing that doesn't make sense, either runtime logic, e.g. object doesn't exist... or base syntax errors.

what you do after that is your problem. it never stops making me laugh how pathetic that directive really is.

ashirazi · 10-17-2004, 12:11 PM

How about those other error checks, like if Err=5.... stuff. What are those if statements looking for?

zchoyt · 10-20-2004, 12:50 PM

if err = 5
is VB's way of checking the err.number against error code 5. Who ever wrote this code used 5 as a "magic number" .

The other way to handle errors in vb is
on error goto tag

so you would have something like:

Code:

public sub My sub
    on error goto tag

    'body of sub

    exit sub

    tag:
    if err.number=4 then
        'action
    elseif err.number-5
        'action
    end if

end sub

This doesn't apply to vbscript. vbscript only has on error resume next.

Check vbforums for more info on VB code.

Hope this helps.