Mar 96 Top 10
|Column Tag:||Symantec Top 10
Symantec Top 10
This monthly column, written by Symantecs Technical Support Engineers, is intended to give our readers technical information on using Symantec products.
By Kevin Quah and Noah Lieberman, Symantec Technical Support
Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.
Q: I am using the Visual Architect and cannot find a way to change the background color of my window. Is there a way to do this using the VA?
A: Although you cannot do this in VA, you can do it programmatically using the toolbox. The class CDocument has a data member macPort, which is a pointer to a GrafPort structure (see below). One of the fields of this structure is rgbFgColor, of type RGBColor. You can set this field with the toolbox call RGBForeColor() which takes an RGBColor as an argument. It will set the rgbFgColor field of the current CGrafPort to the color specified.
If you do not already have an RGBColor ready to pass, you can simply declare one, and set its three fields (between 0 and 65535) to get the color you want.
myRGB.red = 0; // Black
myRGB.blue = 0;
myRGB.green = 0;
The only thing left to worry about is making sure that the right CGrafPort is current when you call RGBForeColor(); a good place to do this is in the MakeNewWindow() function in your CDocument object. A default VA project will produce the file x_CMain.cp (derived from CDocument). Notice the data member itsWindow in the first line. This is a pointer to a CWindow, the one that goes with the default CView in the Visual Architect .rsrc file, Main.
Override x_CMain::MakeNewWindow() in CMain. In CMain::MakeNewWindow(), first call x_CMain::MakeNewWindow, call the Prepare() function of your CWindow object (itsWindow), and call RGBForeColor() to set the color.
Note: Although macPort is declared as a GrafPort, you can get at the CGrafPort fields by casting it to a CGrafPort; e.g., (CGrafPort)macPort->rgbFgColor.
Q: CDialogText seems to report keystrokes to its supervisor, but fails to report cuts and pastes. In the Visual Architect, I chose Classes from the Edit menu and defined a new class. If you type the name of a Library Class, VA will remember it correctly, but if you paste in the name of the Library Class, VA will forget it as soon as you close the dialog box or as soon as you click on another class name in the scrolling list. What is wrong?
A: There is a bug in CDialogText which will be fixed in a later release. For now, please make this change to CDialogText.cp:
virtual voidDoCommand(long theCommand);
/* ID is identifier for this view */
Q: I want to set a breakpoint in a function that is not in the file that is currently displayed in the Debugger window. How do I do this?
A: When you choose Run with Debugger from the project menu, the debugger will come up and place you at the beginning of the program. Switch back to the project manager and double-click the file you want to debug from the project window. Choose Debug File from the Project menu. This will bring you back into the debugger with the chosen file displayed in the debugger window. Now you can set your breakpoint.
Q: Im trying to use floating-point numbers in my VA project using Symantec C++ 7.0.x, and I am getting wildly inaccurate results.
A: By default, a VA project includes ANSI_small++, which does not support floating-point numbers. Remove ANSI_small++ and replace it with ANSI++.
Q: I am familiar with command-line compilers where you would use a -d switch to define something for the entire project. How do you do this in Symantec C++?
A: In the Project Options dialog, select the compiler you are using (for example PowerPC C, or MrC++), and then select the Prefix page. Anything you add to the prefix will be globally defined.
Q: I have a single-segment code resource that was working fine. Now that I have made it multi-segment, it is crashing all over the place. I am not using any globals, so I should not need to set up A4 - right?
A. In multi-segment code resources, THINK C stores string literals the same way as globals. If you are using literals and constants, you still need to set up A4. In single-segment code resources, string literals are stored in code and you dont need to set up A4 to use them. Symantec C++ handles string literals in code resources in the same way that THINK C does - unless you turn on Put String Literals in Code on the Compiler Options page of the Options dialog. Then, Symantec C++ will store string literals in code, and you will not need to set up A4 to use them.
Q: I need to access a data member or member function of my CApp class. How do I do this?
A: In CApp.h, add this statement:
#define gApp ((CApp*)gApplication)
Now gApp will be a globally scoped pointer variable that you can use to access your CApp member functions or data members.
Q: I would like to use the MrC and MrC++ translators to compile an existing SPM C/C++ project. How do I do this?
A: a. Choose Options from the Project menu.
b. Click on the Extensions icon in the left scrolling window.
c. Select the .c file extension.
d. Set the Translator popup menu to SPM MrC.
e. Click on the Replace button.
Repeat steps (c) though (e) for .cp and .cpp file extensions, except set the Translator for both extensions to SPM MrC++. Click Save. Update and run your project.
The SPM MrC and MrC++ translators take a longer time to compile, but they produce code that is highly optimized. To view performance benchmarks visit the website:
We recommend that you use the default translators (PowerPC C and PowerPC C++) during the earlier phases of development for fast edit-compile-debug cycles, and then switch to SPM MrC or MrC++ to create the later optimized builds of the product.
Q: I am trying to use the new MrC/MrC++ compiler off the Release 4 CD, and even on the most basic projects I am getting strange link errors such as: undefined symbol .B2S997, .B2S998, .B2S999. Am I doing something wrong?
A: In order to use the SPM MrC or MrC++ compilers, you must use the latest Symantec Project Manager 8.04d11 (or later). It may be found in the Pre-release Symantec C++ for Power Mac folder.
Q: My project now uses SPM MrC and SPM MrC++ translators. When I compile I get the warning:
Prefix "SPM MrC++";
While compiling "main.cp"
Warning: debugging symbols can't be generated with optimizations on
What is wrong?
A: It is not possible to debug optimized code with MrC/MrC++. If you select Optimizer On and also check the debug diamond in the project window, no debug information will be generated and you will get a warning to that effect.
In the January MacTech Magazine Symantec Top 10 article, there was a question regarding how to add note files and ReadMe files to a SPM project. The solution was to make a <<none>> translator and map this to an extension such as .note. This procedure is not recommended and may cause project corruption.
There are two correct methods for adding non-source files to a project. Either hold down the command-key and drag a file to the project window (drag-and-drop method), or choose Add Files... from the Project menu, and then select All Files from the Show: popup menu. You can then add non-source files to your project. For more information, please consult pp. 16-17 of your Users Guide.
Special Thanks To:
Michael Hopkins, Andrew McFarland, Yuen Li, Mark Baldwin, Glenn Austin, Craig Conner, Tom Emerson, John Micco and Jeff Weeks.