Mar 95 Top 10
|Column Tag:||Think Top 10
Think Top 10
This monthly column, written by Symantecs Technical Support Engineers, aims to provide you with technical information based on the use of Symantec products.
By Michael Hopkins and Craig Conner, Symantec Technical Support
Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.
This month well cover the PowerPC and Symantecs C++ Cross Development Kit.
Q: How do I debug my PowerPC application?
A: The Symantec PowerPC Cross Development Kit does not include an integrated source-level debugger. You have three options for debugging.
1) The CDK includes Apples two machine PowerPC debugger which allows you to send debugging info from the PowerPC running the application to a non-PowerPC machine connected via the serial port. Although this is a very good debugging environment, it requires an extra machine.
2) An alternative is to use Apples single machine debugger, available from Apple as a pre-release version.
3) Perhaps the best alternative is to compile your code under the 68K compiler and thoroughly debug it using the integrated Symantec Debugger. Once your program is debugged, you should be able to recompile it using the PowerPC compiler without modifying the runtime behavior.
Q: I am getting bus errors when I run my PowerPC code. How do I find dangling pointers in my programs?
A: When you create pointer variables, set them to the value (void *)0xDEADBEEF. This is an odd address and you do not need to worry about it being a valid address on Macintosh NuBus cards (the address lives in slot Ds superslot space). Any time you dereference such a pointer before assigning a value to it, you will get either a bus error or an address error. This technique also works for 68K code.
Q: How do I make a fat binary application using the CDK?
A: Build your application with the 68K compiler, and then add your resulting application file to your PowerPC project. When you build the PowerPC app, the environment will copy the 68K resources (including the 68K 'CODE' resources) into the final app along with a 'cfrg' resource and the PPC code (in the data fork).
Q: I am in the process of porting some scientific applications written in C to the PowerPC. I run into all kinds of problems when compiling it with the C++ compiler. Is there a native PPC C translator available for the CDK?
A: Yes, we do have a native C translator available as well as a complement of Standard C Libraries. If you would like to receive a copy, give us a call at (503) 465-8470, send us a message at d0152 on AppleLink, or email us at email@example.com. Be sure to include your name and mailing address with your request. Allow 5-10 days for shipping.
Q: I am trying to compile my PPC project and I get a link error "undefined main()". What causes this?
A: The current version of the THINK Project Manager is not capable of hosting a runtime PowerPC environment. You will get this error if you choose Run from the Project menu. Instead, you should compile the project by choosing Bring Up To Date, and then choose Build PowerPC App from the AppleScript menu to build your executable.
Q: I am trying to compile my program using the CDK and the PowerPC C compiler and I am getting the warning: "File <stdio.h>; Line 28; While compiling 'myfile.c' Warning: Warning: The Symantec ANSI libraries require mapcr to be turned off". What should I do?
A: Go into your standard library folder and rebuild those libraries that you are including in your project. The libraries that will most likely need rebuilding are PPCANSI.o and PPC CPlusLib.o.
1) For each library you want to rebuild, find and open the corresponding project file (PPC ANSI.o is PPCANSI.Π, PPC CPlusLib.o is PPCCPlusLib.Π ).
2) Choose Remove Objects to make sure that all of the source files are recompiled.
3) Go to the compiler settings page for both PowerPC C and PowerPC C++ (under Edit, Options, PowerPC C or PowerPC C++ ) and uncheck the Map carriage returns check box.
4) Bring the project up to date.
5) Use the Build PowerPC Lib script to create the library.
Q: I just installed the CDK patch version 126.96.36.199 and when I rebuild the ANSI libraries, I get errors "Undeclared FATANX, FFEXT", and "FX2DEC" in math.c, printf.c, and scanf.c. How do I fix this?
A: There is an error in the fp.h file from the CDK 188.8.131.52 patch which causes these problems. This will be fixed in the next update. To work around it, do the following:
In the Universal Headers folder, rename fp.h to PowerPCfp.h.
Create a new file named fp.h in the Universal Headers folder containing the following:
#if defined(powerc) || defined(__powerc)
Q: I am trying to build PPCTinyEdit.Π with the CDK and I get an error from ToolServer "PPCBuild.out error MarkReleaseObject :: new failed error -108". What is causing this and how can I fix it?
A: An error code of -108 is a system error that indicates that you do not have enough room in your heap zone. Increase your memory partition for ToolServer and the problem should go away.
Special Thanks to Glenn Austin, Mark Baldwin, and Colen Garoutte-Carson.