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Volume Number: 11
Issue Number: 5
Column Tag: Symantec Top 10
Symantec Top 10 
This monthly column, written by Symantec’s Technical Support
Engineers, aims to provide you with technical information based on the
use of Symantec products.
By Colen Garoutte-Carson, Quality Assurance & Technical Support, Symantec Corp.
Note: Source code files accompanying article are located on MacTech CD-ROM orsource code disks.
Q: How do I build a fat application with Symantec C++ v8.0?
A: We’ve touched on this before, and here’s a more detailed look. When an application
is launched on a 68K Macintosh, the operating system (OS) loads and executes a 68K
‘CODE’ resource ID 1. When an application is launched on a PowerMac, the OS first
looks for a ‘cfrg’ resource describing a PowerPC code fragment stored in the
application’s data fork, and if found, prepares and executes the PowerPC code
fragment. If the OS is unable to launch the application this way, it tries to loads and
execute a 68K ‘CODE’ resource ID 1.
A fat (fat-binary) application has both a PowerPC code fragment and 68K
‘CODE’ resources, and can be launched on either platform.
To create a fat binary app, enable the option to merge an existing 680x0
application into your final application, in the project Options dialog, in the
Project Type settings for an application. This copies all resources from the 68K
application that do not already exist in your PowerPC application. Most importantly,
this copies all 68K ‘CODE’ resources to your PowerPC application.
Resources in your 68K application with the same type and ID as those in your
PowerPC application will not be copied.
You can also build a fat application by including a 68K application’s ‘CODE’
resources in a resource (.rsrc) file, and adding that resource file to your PowerPC
project.
Q: How do I create an accelerated code resource?
A: Although the linker in Symantec C++ v8.0 does not yet support the creation of code
resources, there is a way to create a code resource from a PowerPC application using
Symantec Rez. Symantec C++ v8.0 includes a Code Resource project model which does
this.
The Code Resource project model consists of two projects. The first, Code
Resource.π, is similar to a Mac Application project, but doesn’t include
InitToolbox() (it’s unnecessary in a code resource). It uses the
rsrcMPWPPCRuntime.o runtime library instead of PPCRuntime.o, and PPCLink &
MakePEF instead of the internal linker.
In PowerMac applications, constructors and destructors for global and static
objects are called automatically by __cplusstart(), which the linker assigns as the
main entry point to your application (not main()). This routine calls your
constructors, initializes your QuickDraw globals, calls your main() function, and then
calls your destructors.
In a shared library, constructors for global and static objects are called by
__cplusinit, which the linker assigns as an initialization routine. The Code
Fragment Manager will automatically call this initialization routine when your shared
library is loaded. The __cplusinit() routine will also hook your shared library’s
QuickDraw globals into the QuickDraw globals of the calling application. Destructors
for global and static objects are called by __cplusterm(), which the linker assigns as
a termination routine. The Code Fragment Manager will automatically call this
termination routine when your shared library is unloaded.
In code resources, there is no way to automatically call constructors or
destructors for global and static objects, or hook QuickDraw globals, and still preserve
the arguments passed to main(). Instead, you must call routines to do this for you. In
C, you use __rsrcinit() and __rsrcterm(), declared in stdlib.h. In C++, you use
__cplusrsrcinit() and __cplusrsrcterm(), declared in new.h. The C++
initialization and termination routines call the C initialization and termination
routines. Use only the C++ or C initialization routines. Do not use both. These
routines are defined in the rsrcMPWPPCRuntime.o library.
If your code resource is called only once to perform its function, call
__rsrcinit() or __cplusrsrcinit() at the start of your program, and
__rsrcterm() or __cplusrsrcterm() at the end.
If your code resource is reentrant, call __rsrcinit() or __cplusrsrcinit()
only the first time your code resource is called, and __rsrcterm() or
__cplusrsrcterm() the last time your code resource is called.
Do not use any QuickDraw globals, or any global or static objects that rely on
their constructor, before calling __rsrcinit() or __cplusrsrcinit().
The second project in the Code Resource project model will copy the data fork of
the target built by Code Resource.π into a resource and prepend a routine descriptor
to it. Code Resource.π is included as a sub-project to the second project. Debugging
is disabled for the sub-project to ensure that the sub-project’s target is built instead
of a temporary instant-run PEF when the parent project is brought up to date.
__AppendRoutineDescriptor.r.
_CopyToResource.r reads the data fork of the sub-project’s target and stores it
into a temporary resource.
__AppendRoutineDescriptor.r prepends a routine descriptor to the temporary
resource and stores it in your final resource. Before you build your code resource,
you will need to modify a number of #define’s in this file. The file contains comments
that describe the necessary changes.
that the resource description files’ dependency on the sub-project’s target is properly
tracked.
__AppendRoutineDescriptor.r is dependant on _CopyToResource.r. These
files have been named to compile in the right order.
Once the parent project has been brought up to date, your accelerated code
resource will be stored in the project’s resource file (.rsrc ).
Q: How do I create a fat or safe fat code resource?
A: You can build a fat or safe fat code resource in much the same way that you would
create an accelerated code resource, discussed above. The Code Resource project
model includes support for these fat code resource types, as well as a few others. See
the comments within the project model for details.
Q: Why are my structs a different size in my PowerPC project than they are in my
68K project?
A: The MC68000 chip must reference word or long values from even addresses. More
recent chips in the 680x0 family do not have this limitation, but perform faster when
referencing word or long values from even addresses. The 68040 and PowerPC chips
perform even faster with structures aligned on 4-byte boundaries.
If you need to share data structures in memory between 68K and PowerPC code
(e.g. when passing data to the Macintosh Toolbox’s pre-existing 68K-based
interfaces), or need to read or write data structures from/to disk with both 68K and
PowerPC code, you will need to ensure that your alignment settings match in both your
68K and PowerPC projects.
By default, the PowerPC compilers align fields within structs on 4-byte
boundaries. By default, the 68K C++ compiler aligns fields within structs on 2-byte
boundaries. Think C always aligns fields within structs on 2-byte boundaries.
The PowerPC compiler supports the following #pragma directive to enable 68K
(2-byte) structure alignment in a given structure declaration :
#pragma options align=mac68K
/* Your struct declaration */
#pragma options align=reset
Q: My 68K application, created with the Visual Architect in v7.0(.x), works fine.
Why does a fat version of the same application not run on a 68K Mac?
A: Because of changes in the TCL, you will need to re-compile the 68K application
with the 68K environment and TCL included in version 8, and re-merge it into your
fat application.
Q: When I run my program with the debugger, it launches “Power Mac
DebugServices”. This program remains running invisibly. How can I quit this
application when I am done debugging?
A: You can write an AppleScript that contains the following :
tell application "Power Mac DebugServices" to quit
Never run this script while debugging. To ensure that DebugServices has quit when no
script will be run when you quit the Symantec Project Manager.
Q: Can I use Apple’s new Toolbox Assistant with the Symantec Project Manager?
A: Yes. The Symantec Project Manager supports both The THINK Reference and
QuickViewer. It is capable of using both simultaneously.
As with the Think Project Manager, the Symantec Project Manager will allow you
to reference the Think Reference or QuickViewer directly if an alias to it, named
exactly “THINK Reference” or “Primary Doc Server”, is located in your “(Tools)”
folder. The Symantec Project Manager considers these names synonymous. The
Symantec Project Manager will search a second documentation server if it’s
unsuccessful in finding a match in the first. The second documentation server’s alias
must also be located in the “(Tools)” folder and must be named “Secondary Doc
Server”.
Q: When I convert my Think Project Manager project, the Symantec Project Manager
preserves the segmentation in groups. Is there a way around this?
A: Yes, hold down the shift key when opening the Think Project Manager project.
Q: How do I Check In files to my SourceServer database for the first time? And
how do I Check Out files from a SourceServer database that I’ve never checked out
before?
A: To do these actions, you must send the command to SourceServer manually. The
Symantec Project Manager includes a Worksheet window, available under the
Windows menu, that you can use to send commands to SourceServer or ToolServer.
Example of a CheckIn command :
CheckIn -new "filename.cp
Q: Can I use Check In on the Revision menu to check in header files to a
SourceServer database?
A: Yes. In the project Options dialog, on the “Extension” settings page, add .h to
the list of supported filename extensions, but do not specify a translator. You will be
able to add files with names ending in .h to your project, but they will not be compiled.
You can then check these files into your SourceServer database by selecting them in the
project window, and then selecting Check In from the Revision menu.
Referenced by (2):