Contributor: SWAG SUPPORT TEAM SECTION 16 - OWL/BWCC GENERAL INFORMATION This document contains information that is most often provided to user of Section 16 - OWL/BWCC. There is a listing of common Technical Information Documents that can be downloaded from the libraries. There is also a description of the five questions most frequently asked in Section 16 - OWL/BWCC and their answers. TECHNICAL INFORMATION DOCUMENTS TI1203 Using Validators in OWL Applications TI1262 Installation notes regarding Turbo Debugger for Windows TI1171 Borland problem report form TI607 Description and illustration of printing in Windows TI992 Demonstration of collections and listboxes in Windows FREQUENTLY ASKED QUESTIONS Q: "Why do I get 'Application Error -1' when my dialog tries to execute?" A: This is basically a "Failure to create window" error. Most often it is caused by one of two things: 1. Failure to include "BWCC" in your USES clause. If you designed a dialog in Resource Workshop using the Borland "look and feel", you need to include "BWCC" in your USES clause. 2. Incorrect dialog identifier passed to dialog's Init method. Make sure the identifier you are passing to the dialog's Init method is the same one you are using in Resource Workshop. Q: "How can I obtain the latest copy of BWCC.DLL?" A: Download BWCC.ZIP from library 2. Q: "What causes the 'Data Segment too large' compiler error? How do I get rid of it?" A: This error occurs when your application has more than 64K of information that it is trying to put into your its data segment. Note that you only have one 64K data segment to work with, so you should manage this memory judiciously. The following data is kept in an Object Windows application's data segment: * All global variables * All typed constants * Stack * Local Heap (used internally by Windows) * Virtual Method Table To avoid this error, you should take the following steps: * Avoid large global variables. Try instead declaring larger variables on the heap using New() or GetMem(), and keeping a pointer to that variable globally. * Avoid frequent use of string literals and variables in your application. Instead, keep your strings in a resource and use the LoadString API function to load them into memory. * Keep your stack down to a reasonable size. 8K is usually a good amount for most applications. * Avoid making functions in your objects Virtual unless they have to be; this will reduce the size of the Virtual Method Table. Q: "How can I enable or disable a particular control in a dialog box? A: Use the EnableWindow(Wnd: Hwnd, Enable: Bool) API function. It takes two parameters, the handle to the window (remember a control is a window) to be enabled/disabled and a boolean value - True for enable and False for disable. Q: "How do I obtain the handle or ID of a control?" A: If you have a pointer to a control object, OWL will give you the window handle automatically through the HWindow field; PointerToMyControl^.HWindow is the window handle. If you know the handle of a control, you can obtain the ID by calling the GetDlgCtrlID() API function: ControlID := GetDlgCtrlID(ControlHandle); If you don't have a pointer to your control, but know the ID of a control, you can obtain the handle by calling the GetDlgItem() API function: ControlHandle := GetDlgItem(DialogHandle, ControlID); Q: "How can I put Object Windows objects in a DLL?" A: OWL was not designed to be used in a DLL. Some users have managed to get this to work in some cases, but it is not a practice that Borland recommends. For info on launching windows and dialogs from a DLL without OWL, download APIDLL.PAS from library 2. Q: "Can a TFileWindow object edit files larger than 64K?" A: No. A TFileWindow is really just a multi-line edit control that takes up the whole client area. An edit control's buffer is allocated from the local heap, and therefore is usually much smaller than 32K. If you would like to have more buffer space, download GLBEDT.ZIP from library 8 - this file provides you with a greater buffer for the TEdit and TFileWindow objects. Q: "How do I apply to become a beta tester for a future Borland Pascal product?" A: Download SURVEY.ZIP from library 2.