Nov 95 Top 10
- Jan 95 Top 10
- Feb 95 Top 10
- Mar 95 Top 10
- Apr 95 Top 10
- May 95 Top 10
- Jun 95 Top 10
- Jul 95 Top 10
- Aug 95 Top 10
- Sep 95 Top 10
- Oct 95 Top 10
- Dec 95 Top 10
Volume Number: 11
Issue Number: 11
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 Levi Brown, Symantec Corp.
Note: Source code files accompanying article are located on MacTech CD-ROM orsource code disks.
Q: I set my project’s preferred and minimum memory partition sizes in the
“Project Type” window, but when I build my application, the preferred and
minimum memory partition sizes are always set to a different value. What is
wrong?
A: The project’s resource file contains a SIZE resource that always overrides the
problem, open the ProjectName.rsrc resource file with ResEdit and delete the
SIZE resource.
Q: I have heard of this program called Discipline that works with MacsBug to
provide a higher level of error checking. What does it do, and does it work with
the Symantec Debugger?
A: Discipline is a system extension that works with MacsBug to check the arguments
passed to Toolbox routines. Discipline is built into MacsBug 6.5d12. To access
it, you use the dcmd dizy.
Our debugger has not been tested thoroughly with Discipline. Therefore, it is
possible that you may run into some incompatibilities. Discipline has a habit of
revealing problems with many different programs including the Finder, which
makes it difficult to use as a debugging tool.
Q: In UNIX there is a collection of routines, declared in curses.h that can be used to
manipulate the cursor in a console-like display. In my Symantec C++ 8.0
project using the console window how can I achieve similar results?
A: Most of the functionality of the console window is declared in console.h. Here
is an example of how to move the cursor to a specific point, and clear everything
in the window from that point down.
#include
#include
main()
{
int i, ch, rows = 12, cols = 40;
console_options.nrows = rows;
console_options.ncols = cols;
cshow( stdout );
csetmode( C_NOECHO, stdout );
// Set mode to C_NOECHO, so
// getchar doesn’t move the
// cursor.
for( i=0; i
putchar( 'x' );
cgotoxy( 5, 3, stdout );
ch = getchar();
ccleos( stdout );
}
Before the call to ccleos()
After the call to ccleos()
Q: I’m using the ToolBox call GetPicture() and I want to clean up the memory after
I am done with the picture. How do I do that?
A: Pass the handle that GetPicture() returns to ReleaseResource(). Do not call
DisposeHandle() on a handle to a resource or you may corrupt the resource
map.
Q: When I try to use the QuickDraw global variables in my Symantec C++ 8.0
project I get undefined symbol errors. I’ve used the same globals many times
before using 7.0 and it worked just fine. What is happening here?
A: With the introduction of Apple’s Universal Headers, access to the QuickDraw
globals changed. Your 7.0 project was probably referring to the QuickDraw
globals in the “old” style and using the original header files, not the Universal
Headers. You will need to access the QuickDraw globals through the qd struct,
defined in Quickdraw.h. i.e.:
CopyRgn(thePort->visRgn, thePort->clipRgn);
would become
CopyRgn(qd.thePort->visRgn, qd.thePort->clipRgn);
Q: I have a large 8.0 project with many files and I frequently use the Find...
parameters each time. Is there a way to set default search parameters?
A: Yes! In your Symantec C++ folder there is a folder called (Scripts), inside
tell application "Symantec Project Manager
-- Set the default search state.
set user search state to
{wrap around:true,
ignore case:true,
files to search:only sources,
exclude system:true,
exclude precompiled header:true}
end tell
You can set the default parameters for the find in the indexed list shown above.
Q: I get link errors with a class that has static data members. Why is this?
A: If you declare a class with static data members you need to initialize those data
members in the global data space outside the class, so that memory is allocated
for them. If you do not initialize the static variables in global data space outside
the class then the compiler does not have a location for the static data members in
memory. Thus, you get a link error when you attempt to access that variable.
Example:
class A
{
public:
static short x;
static char y;
char z;
};
short A::x = 0; // Note: These variables are initialized
char A::y = 'a'; // outside the class declaration in
// order to allocate memory for them.
Q: The following code used to work (up through 8.0), but in 8.0.1 it doesn’t. Why?
class A
{
friend class B;
public:
A();
~A();
B *GetFriend(int index);
};
class B
{
public:
B();
~B();
int index;
};
*GetFriend(int index), it works. Is it a compiler bug, or is it a new ANSI
rule of some kind that I didn’t know about?
A: A couple things are happening here:
First, the code above compiled in previous versions due to a compiler bug. 8.0.1
B is yet, and thus the compiler complains. If you put a forward declaration,
Second, the statement friend B *GetFriend(int index) tells the compiler
private members. The statement B *GetFriend(int index) tells the compiler
members.
Q: I have made a floating window view in Visual Architect, but when I go to attach it
to a command, it does not appear in the list of views to open. How do I open it?
A: When you make a floating window view, VA derives a class from
CFloatDirector; we will call it CMyFloatingWindow. You need to call
OpenWind() to make the window appear (ShowWind() only undoes a
HideWind()). The easiest way is to call it from within
CMyFloatingWindow::MakeNewWindow(), right after the object is created; the
window will appear immediately upon launch. To have it open from a command
(i.e. menu or button), create the command by choosing Commands... from the
popup menu.
Next, attach the command to the menu or button. If attaching to a menu: choose
select the item and choose the command you created from the Command: popup
menu. If attaching to a button: select the button in VA, get Pane Info from the
Pane menu, open the CButton triangle and choose the command you created from
the Command: popup menu.
Visual Architect will generate an empty function, DocmdOpenMyFWindow inside
x_CApp.cp. Call OpenWind() from here.
Note: Calling from outside the CMyFloatingWindow requires that you have a
pointer to the CMyFloatingWindow object. You can find this declared as a global
in x_CApp.cp in the form:
extern CAFloatingWindow *gCAFloatingWindow;
If you wish to make the call to OpenWind() from someplace other than
x_CApp.cp, you must redeclare it (as above) and #include
CMyFloatingWindow.h in the file where you want to use it.
Q: When I try to run the Symantec Debugger it quits with an error that says,
“DebugServices cannot set trace bit.” How do I set the trace bit? I can’t find any
options to set a trace bit in any of the project option debugging screens.
A: Most likely, you are running a Pre-System 7.5 operating system. You will need
to put the items that are in the Pre-System 7.5 Additions folder into your system
folder. The Pre-System 7.5 Additions folder is found in the Apple Software
folder on your Symantec C++ 8.0 CD-ROM.
Bonus:
Q: I’m porting my code from 7.0.x to 8.0 and I get an “undefined symbol
MBarHeight” when I try to compile. Why do I get a linker error?
A: With the introduction of Apple’s Universal Headers you can no longer access the
variable MBarHeight directly. You will need to include LowMem.h and use
LMGetMBarHeight(), and LMSetMBarHeight(), to access menu bar height.
Access to other low memory variables has been changed in similar ways, so it’s a
good idea to look in LowMem.h if you plan on using low memory variables.
Special Thanks To:
Glenn Austin, Mark Baldwin, Craig Conner, Rick Hartmann, Michael Hopkins, Steve
Howard, Noah Lieberman, Andy McFarland, Chris Prinos, and Kevin Quah.
Referenced by (2):