Writing Console-Mode Applications in Visual Basic
Visual Basic, as was mentioned earlier, has no built-in support for console work of any kind. This means that all of our interfacing with the console will be done through calls to the Win32 API. Our application has no attachment to the console box. It's not a resource of any kind, it's a process that we request the operating system to allocate for us. This is done by a call to the API function AllocConsole, whose prototype is as follows:
Private Declare Function _ AllocConsole Lib "kernel32" () As Long
This will create a console window in which we can print and receive input. This console window - this is important to remember - is a process controlled by the operating system. Think of all operations that we perform on it as "requests" (and these requests can be denied). Since it is a process, it must always be destroyed when we are done with it, or before the application terminates. We destroy the console process with the FreeConsole function.
Private Declare Function _ FreeConsole Lib "kernel32" () As Long
With this done, one can already write a program that brings up a console box and closes it:
Private Declare Function _ AllocConsole Lib "kernel32" () As Long Private Declare Function _ FreeConsole Lib "kernel32" () As Long Private Sub Main() AllocConsole FreeConsole End Sub
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