gcc BUG or something special ...

[Andreas Otto]

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Hash: SHA1

Hi,
I have the following code:

MqFactoryCtxIdentGet (struct MqS * const context) {
printP(context)
printP(NULL)
printI(context)
printI(NULL)
printI(context != NULL)
printI(context == NULL)
MA
if (context && context->setup.factory) {
M0
return context->setup.factory->ident;
} else {
M1
return "";
}
}

- -> the print??? is debugging output, "P" as pointer, "I" as integer

I call the code 2 times,
1'st with a valid pointer as input ...
2'nd with NULL as input

and now the result:

MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:508:26150:0x7fd801319700)
- -> (MQ_PTR)context<0x961880>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:509:26150:0x7fd801319700)
- -> (MQ_PTR)((void *)0)<(nil)>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:510:26150:0x7fd801319700)
- -> context<9836672>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:511:26150:0x7fd801319700)
- -> ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:512:26150:0x7fd801319700)
- -> context != ((void *)0)<1>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:513:26150:0x7fd801319700)
- -> context == ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:514:26150:0x7fd801319700)
- -> AAAAAAAAAAAAAAAAA
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:516:26150:0x7fd801319700)
- -> 00000000000000000
- ---- init-3-(1|binary|pipe|ruby.pipe.pipe) start
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:508:26150:0x7fd801319700)
- -> (MQ_PTR)context<(nil)>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:509:26150:0x7fd801319700)
- -> (MQ_PTR)((void *)0)<(nil)>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:510:26150:0x7fd801319700)
- -> context<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:511:26150:0x7fd801319700)
- -> ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:512:26150:0x7fd801319700)
- -> context != ((void *)0)<1>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:513:26150:0x7fd801319700)
- -> context == ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:514:26150:0x7fd801319700)
- -> AAAAAAAAAAAAAAAAA
..../theLink/example/ruby/server.rb:458: [BUG] Segmentation fault


why is (NULL != NULL) = 1 ?????????????????


mfg, Andreas Otto
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[Ben Pfaff]

I have the following code:

MqFactoryCtxIdentGet (struct MqS * const context) {
printP(context)
printP(NULL)
printI(context)
printI(NULL)
printI(context != NULL)
printI(context == NULL)
MA
if (context && context->setup.factory) {
M0
return context->setup.factory->ident;
} else {
M1
return "";
}
}

Is this really your code? If so, then you left out several
important structure and macro definitions. What are they?

 

[Andreas Otto]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Am 13.01.2011 19:32, schrieb Andreas Otto:

Hi,
I have the following code:

MqFactoryCtxIdentGet (struct MqS * const context) {
printP(context)
printP(NULL)
printI(context)
printI(NULL)
printI(context != NULL)
printI(context == NULL)
MA
if (context && context->setup.factory) {
M0
return context->setup.factory->ident;
} else {
M1
return "";
}
}

-> the print??? is debugging output, "P" as pointer, "I" as integer

I call the code 2 times,
1'st with a valid pointer as input ...
2'nd with NULL as input

and now the result:

MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:508:26150:0x7fd801319700)
-> (MQ_PTR)context<0x961880>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:509:26150:0x7fd801319700)
-> (MQ_PTR)((void *)0)<(nil)>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:510:26150:0x7fd801319700)
-> context<9836672>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:511:26150:0x7fd801319700)
-> ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:512:26150:0x7fd801319700)
-> context != ((void *)0)<1>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:513:26150:0x7fd801319700)
-> context == ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:514:26150:0x7fd801319700)
-> AAAAAAAAAAAAAAAAA
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:516:26150:0x7fd801319700)
-> 00000000000000000
---- init-3-(1|binary|pipe|ruby.pipe.pipe) start
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:508:26150:0x7fd801319700)
-> (MQ_PTR)context<(nil)>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:509:26150:0x7fd801319700)
-> (MQ_PTR)((void *)0)<(nil)>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:510:26150:0x7fd801319700)
-> context<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:511:26150:0x7fd801319700)
-> ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:512:26150:0x7fd801319700)
-> context != ((void *)0)<1>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:513:26150:0x7fd801319700)
-> context == ((void *)0)<0>
MqFactoryCtxIdentGet(../../../theLink/libmsgque/factory.c:514:26150:0x7fd801319700)
-> AAAAAAAAAAAAAAAAA
.../theLink/example/ruby/server.rb:458: [BUG] Segmentation fault


why is (NULL != NULL) = 1 ?????????????????


mfg, Andreas Otto

solved ... had a " __attribute__((nonnull));" for the first argument in
the header file ... optimizer throw away the check code


mfg, Andreas Otto
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