How do you use CreateFile?

[Tom Anderson]

Trying to use API GetTapeStatus to determine if tape is inserted in tape drive. Must use CreateFile to get handle to the device (Tape0). All examples are C++. How do you use this API from VB6?

[Lothar Haensler]

try this:

option Explicit
private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (byval lpFileName as string, byval dwDesiredAccess as Long, byval dwShareMode as Long, lpSecurityAttributes as SECURITY_ATTRIBUTES, byval dwCreationDisposition as Long, byval dwFlagsAndAttributes as Long, byval hTemplateFile as Long) as Long
private Const OPEN_EXISTING = 3
private Type SECURITY_ATTRIBUTES
nLength as Long
lpSecurityDescriptor as Long
bInheritHandle as Long
End Type
private Const GENERIC_READ = &H80000000
private Const INVALID_HANDLE_VALUE = -1
private Declare Function CloseHandle Lib "kernel32" (byval hObject as Long) as Long

private Sub Command1_Click()
Dim lResult as Long
Dim sa as SECURITY_ATTRIBUTES
sa.nLength = len(sa)
lResult = CreateFile("c:\test.txt", _
GENERIC_READ, 0, sa, OPEN_EXISTING, 0&, 0&)
If lResult = INVALID_HANDLE_VALUE then
MsgBox "cannot open"
else
Call CloseHandle(lResult)
End If
End Sub



it doesn't take tape drives into account, as I don't have access to one, but it shows you the APIs and it has been tested in VB 6, NT 4