Oct 96 Top 10
|Column Tag:||Symantec Top Ten
Symantec Top 10
By Craig Conner
Q: I know that if I use the java.lang classes which extend number, like Double, Float, Integer and Long, I can get their values as a string without difficulty, however, I dont like to use these classes and want to know how to coerce a standard number type into a string. For example, in C I could use sprintf(&str, %d, num); where num is some variable of type int and the contents of the string str would contain the value of num. How do I do something similar in Java?
A: There is a simple and elegant method to do just this. You can take advantage of the + operator in Java to add a string and a variable together. For instance, say you had an integer y that you wanted to be displayed next to the string Output: , you could do this by using the + operator: Output: + y. If we assign an arbitrary value for demonstration purposes to y, say 5, then the result of the expression would be a string with contents Output: 5. So what if you just want the value of your variable as a string, without anything else? You could use this expression: + y. This results in a string that contains just the value of y as a string. This is handy when you want to output the contents of a variable to the system error window for debugging purposes like this: System.err.println( + y);
Q: In Symantec Café I want to make a standalone application so I setup my project to be an application rather than an applet, but when I get done building the project all I have is a .class file that presents the Applet Viewer upon double clicking. Can I make a stand alone application using Café?
A: Currently the only way to run the byte code that the Java compilers produce is through an applet viewer or through a Java capable browser. The major difference between generating an application rather than an applet in Café is that the security issues are not restrictive in an application, as they are in an applet. By generating an application, you are still generating Java byte code, not machine code native to the platform. This means that that byte code will still need to be interpreted at runtime by some implementation of a Java virtual machine, whether it is the Applet Viewer or a Java capable browser. Rumor has it that, in the future, Mac OS 8 will have a Java virtual machine built in. Ah, Mac OS 8.
Q: On the PPC, are floating point numbers aligned on the stack?
A: Normally floating point values are stored in floating point registers unless you are using the address of the floating point value. The significance of this is that, if the stack is not aligned on an 8-byte boundary, access to that double can be extremely slow due to misaligned accesses.
Q: How can I create a 68k code resource in the release 5 Symantec Project Manager?
A: You will need the 68K Code Resource project model and
files, available at:
ftp://ftp.symantec.com/public/devtool/mac/developer.tools.and.info/SPM68KCodeResource.hqx. Since the SPM currently creates a SIZE resource for 68K applications, you will need to execute the *Remove SIZE Resource* AppleScript from the menu after building your code resource.
Q: I want to create a PPC shared library, but it appears that exporting names from the library is an all-or-nothing affair. How can I export only certain names from my library?
A: Use #pragma export list name[,name[...]] to specify certain names to export. Conversely, importing certain names is done through the #pragma import list name,[name[...]] option.
Q: How can I quickly calculate the ProcInfo value procInfoConstant, if Ive defined it in my program?
A: Add the line long pinfo = procInfoConstant; as the first line in your main function, then disassemble your PPC code. Youll find the value of the procInfo constant as a decimal value loaded into a register with an LI instruction (it should be the first LI in the main function), and the hexadecimal value will be the low word of the hex value to the left of that LI instruction.
Q: I notice that when I am linking my 68k project in the release 5 Symantec Project Manager it can take a really long time. Is there a way to speed up this process?
A: Yes! We are using the ToolServer, an external application, to invoke the LINK tool in order to perform the linking process. Since the ToolServer comes up in the background, link times are often longer than they need to be. To avoid this, and to speed up linking time for your 68k projects, simply bring the ToolServer to the front during linking.
Q: I have a PPC application that runs flawlessly in Native PPC but when I run the 68k version it causes runtime errors. How do I Debug 68k code generated from the release 5 Symantec Project Manager?
A: The Symantec C++ 8.0 Release 5 CD includes an external debugger called, SourceBug which will allow source level debugging of 68k Applications built with the Symantec Project Manager. Future releases of Symantec C++ will have integrated 68k debugging support.
Q: So now that I know I can debug my 68k project using SourceBug, how do I use it?
A: Here are some steps to help you out:
Install SourceBug onto your hard drive by copying it from Apple Software:Debuggers:SourceBug on your 8.0 release 5 CD.
Under the Project menu, choose Options... then go to the Linker page, select the Output option in the pop-up menu.
Check the option Generate a Symbol file.
Inside the Generate a link file box, select Full symbols. This will cause a myProj.SYM file to be generated when you build the application.
Under the Build menu select Build Application.
Launch SourceServer by double clicking on it from the Finder. You can locate an alias to the SourceServer application by looking in the (Tools) folder inside your Symantec C++ for Power Mac folder.
From the Open dialog, open your 68k Application. The source code browser window will appear.
Click on the main. in the stack crawl pane in the upper left.
Click on the function you would like to debug in the pane to the upper right.
Set break point(s).
Select Run from the Control menu.
Q: How does the Enable Symbolic Debugging check box affect the .SYM output files, and why wont it stay set when I save the Symantec Project Manager Options?
A: The inclusion of this checkbox is actually an oversight. Setting this checkbox, you may notice, had no effect on the symbolic output file that gets created by the linker. (See the linker options for 68k projects.)
Q: Then, how do I create an external symbol file so I can use external debuggers to debug my 68k project?
A: This Option is Set in the Linker page of the Options... item of the Project menu. Once you get to the Linker page, choose Output in the pop-up menu. To turn on External Symbol file generation, check the checkbox Generate a symbol file and select the Full symbols checkbox.
Special thanks to: Glenn Austin, Scott Morison, Andrew McFarland and Mark Baldwin.