Re: Can't mix native exceptions and ObjC++

[Isamu Mogi]

Hi

This is a bug in GCC.

obj-c++.dg/try-catch-[29].mm (objc exceptions are broken) fails with the GNU
Runtime
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23616

Quick and dirty fix here:

#import <Foundation/NSException.h>

#if defined(__cplusplus) && defined(__GNUC__) \
    && defined(GNUSTEP) && defined(_NATIVE_OBJC_EXCEPTIONS)

// gcc 5.4.3
#if  __GNUC__  < 5 ||                    \
    (__GNUC__ == 5 &&                    \
        (__GNUC_MINOR__  < 4 ||          \
        (__GNUC_MINOR__ == 4 &&          \
             __GNUC_PATCHLEVEL__ < 3)))

#undef NS_DURING
#undef NS_HANDLER
#undef NS_ENDHANDLER

#define NS_DURING      @try {
#define NS_HANDLER     } @catch (id) {                                    \
                           NSException* localException =                  \
                               [NSException exceptionWithName:@"Unknown"  \
                                                       reason:@"Unknown"  \
                                                     userInfo:nil];       \
                           {
#define NS_ENDHANDLER      }                                              \
                       }

#endif
#endif

#import <Foundation/Foundation.h>

int main() {
    NSAutoreleasePool* pool = nil;

    NS_DURING
    {
        pool = [[NSAutoreleasePool alloc] init];
        [NSException raise:@"foo" format:@"bar"];
    }
    NS_HANDLER
    {
        NSLog(@"%s", [[localException description] UTF8String]);
    }
    NS_ENDHANDLER;

    [pool release];
    return 0;
}


Isamu


Lucas Schnorr wrote:
> 
> Hi,
> 
> I think I got the same kind of error when dealing with NSException and
> using g++ to compile.
> 
> I have a GNUmakefile:
> 
> include $(GNUSTEP_MAKEFILES)/common.make
> TOOL_NAME = ExceptionTest
> ExceptionTest_OBJC_FILES = source.m
> include $(GNUSTEP_MAKEFILES)/tool.make
> 
> And the source.m like this
> #include<Foundation/Foundation.h>
> 
> int main(int argc, char **argv)
> {
>       NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
>       
>       @try {
>           @throw [NSException exceptionWithName:@"Throwing a test exception"
>                                       reason:@"Testing the @throw directive."
>                                       userInfo:nil];
>       }
>       @catch (id theException) {
>               NSLog(@"%p", theException);
>               NSLog(@"%@", theException);
>       }
>       @finally {
>               NSLog(@"This always happens.");
>       }
>       
>       NSLog(@"Leaving ...");
>       [pool release];
>       return 0;
> }
> 
> Everything works fine during execution:
> 2010-02-22 09:28:40.536 ExceptionTest[6763] 0x14ffed0
> 2010-02-22 09:28:40.538 ExceptionTest[6763] <NSException: 0x14ffed0>
> NAME:Throwing a test exception REASON:Testing the @throw directive.
> 2010-02-22 09:28:40.538 ExceptionTest[6763] This always happens.
> 2010-02-22 09:28:40.538 ExceptionTest[6763] Leaving ...
> 
> But, if a rename the file source.m to source.mm and
> change this line of GNUmakefile from
> ExceptionTest_OBJC_FILES = source.m
> to
> ExceptionTest_OBJCC_FILES = source.mm
> 
> I get this during execution:
> 2010-02-22 09:29:46.653 ExceptionTest[6818] 0x1d3fc60
> Segmentation fault
> 
> GDB helps more or less, it says that the problem is with the NSLog
> when trying to access the theException variable.
> 
> 2010-02-22 09:30:09.355 ExceptionTest[6822] 0x67ecb0
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff728da55 in objc_msg_lookup () from /usr/lib/libobjc.so.2
> (gdb) bt
> #0  0x00007ffff728da55 in objc_msg_lookup () from /usr/lib/libobjc.so.2
> #1  0x00007ffff77eda92 in ?? () from /usr/lib/libgnustep-base.so.1.19
> #2  0x00007ffff7819a09 in ?? () from /usr/lib/libgnustep-base.so.1.19
> #3  0x00007ffff7942154 in ?? () from /usr/lib/libgnustep-base.so.1.19
> #4  0x00007ffff79a8722 in ?? () from /usr/lib/libgnustep-base.so.1.19
> #5  0x00007ffff78d525e in NSLogv () from /usr/lib/libgnustep-base.so.1.19
> #6  0x00007ffff78d4e8d in NSLog () from /usr/lib/libgnustep-base.so.1.19
> #7  0x0000000000400c2b in main (argc=1, argv=0x7fffffffdf78) at
> source.mm:14
> 
> Does anyone know how to handle objective-c exceptions when compiling
> with g++ or a work-around?
> I think in this case I am dealing only with obj-c exceptions (no
> mixing with c++ exceptions),
> so I think it should work.
> 
> Lucas
> 
> 

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