Please forgive me if I'm being dense, I'm very new to Objective-C.
The problem was that a class in GNUMail (PGPController) implemented a
method thusly:
- (NSString *) version
{
return @"v0.9.1";
}
That method is declared in the GNUMailBundle protocol. GNUMail would
segfault when the pointer returned by that method was accessed in any
way. I looked at it in gdb and figured out that the pointer was being
truncated to 4 bytes (I have an LP64 system.) Renaming the method made
the truncation and crash go away.
Object.m declares a "version" class method that returns an int.
NSObject in the GNUStep base library also has a "version" class method
that returns an int. I don't know what the rules are in Objective-C
for overloading by return type, but gcc did not complain when it
compiled PGPController. (The output from gcc 4.1.2 for that class is at
the end of this message.)
Incidentally, what are the rules for overloading by return type? I
looked around and all I found was this:
"Although identically named class methods and instance methods are
represented by the same selector, they can have different argument and
return types."
http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC/Articles/chapter_4_section_6.html
Which makes me think that what GNUMail does should be allowed. I don't
know where the confusion between pointer and int is coming in.
Thanks,
Jose.
x86_64-pc-linux-gnu-gcc PGPController.m -c \
-MMD -MP -DGNUSTEP -DGNUSTEP_BASE_LIBRARY=1
-DGNU_GUI_LIBRARY=1 -DGNU_RUNTIME=1 -DGNUSTEP_BASE_LIBRARY=1
-D_REENTRANT -fPIC -g -Wall -DDEBUG -fno-omit-frame-pointer -DGSWARN
-DGSDIAGNOSE -Wno-import -march=nocona -pipe -fno-strict-aliasing
-fexceptions -fobjc-exceptions -D_NATIVE_OBJC_EXCEPTIONS -fgnu-runtime
-Wall -Wno-import -fconstant-string-class=NSConstantString
-I../../Framework/GNUMail -I.
-I/var/tmp/portage/gnustep-apps/gnumail-1.2.0_pre3/temp/GNUstep/Library/Headers
-I/usr/GNUstep/Local/Library/Headers -I/usr/GNUstep/System/Library/Headers \
-o obj/PGPController.o
PGPController.m:743: warning: incomplete implementation of class
'PGPController'
PGPController.m:743: warning: method definition for
'-bodyWasDecoded:forMessage:' not found
PGPController.m:743: warning: method definition for
'-bodyWillBeDecoded:forMessage:' not found
PGPController.m:743: warning: method definition for
'-bodyWasEncoded:forMessage:' not found
PGPController.m:743: warning: method definition for
'-bodyWillBeEncoded:forMessage:' not found
PGPController.m:743: warning: method definition for
'-composeViewAccessoryWillBeRemovedFromSuperview:' not found
PGPController.m:743: warning: class 'PGPController' does not fully
implement the 'GNUMailBundle' protocol
Andrew Pinski wrote:
On 9/26/07, Jose Quinteiro <[EMAIL PROTECTED]> wrote:
Hello,
The getter/setter for version in Object.M gets/takes an int, and they
eventually get/set the "version" field in struct objc_class. This
field is declared as a long in objc/objc.h.
Why? Any change here will change the ABI so it incorrect thing to do.
So the GNUMail issue seems like people are ignoring warnings that GCC
generates about methods are not declared in the class.
-- Pinski
