app runs in vb environment but not as an exe

[Galyl]

Ive written an app in vb6, in runs perfectly in the vb environment, but when i compile it i get the following error:
Run-time error '5':
Invalid procedure call or argument

this error occurs after a call to a C dll. The dll gets initialised, it retrieves the data it is supposed to from the com port, but when it sends a return code to my vb app, the error occurs.

It runs perfectly in VB. Does anyone have any idea why this happens?

Thanks for your time

 

[chiph]

It sounds like you're passing a string to the C dll. If so, make sure you initialize the string to spaces (or something) before doing this. The way VB and C handle strings are very different, and for the two to talk correctly you need to allocate some memory for the C dll to write into...and you do this by initializing the string first.

Dim MyString as string

MyString = space$(400)
call MyDllFunction(MyString)

(assuming that the DLL will never write more than 399 ASCII characters to the string).

Chip H.

 

[Galyl]

The function im calling is declared as follows :

Private Declare Function BcpSend Lib "vc2vb.dll" (ByVal cmd As Integer, ByVal address As Byte) As Byte

and is called as :

iRet = BcpSend(151, iaddr)

where iRet and iaddr are both bytes. Havnt chaged the names, the were bith integers when i defined them.

iRet get set to 0 before the function call
iaddr contains a variable retrieved from a database

 

[Galyl]

I changed iRet from byte to long, that has solved the problem.

Thanks for the replying