strange problem with self-compiled software on FC 5 T2...

[John Summerfied]

Patrick von der Hagen wrote:
> Ulrich Drepper wrote:
> 
>> Patrick von der Hagen wrote:
>>
>>> Now, whom should I contact? glibc, gnu-c or gnu-c++?
>>
>>
>> Nobody but the person who wrote that code.  You pass a pointer to a
>> 'char' variable for the %s format element.  Even *if* you only read one
>> character the terminating NUL byte will overwrite the next byte.  That's
>> likely your variable 'j'.
> 
> It's really amazing how many people missed that one and that several 
> compilers (e.g. gnu-gcc/g++ 3.5) produced binaries that worked 
> flawlessly. But you are right, "c" was placed next to "j" in memory, so 
> j has been damaged by invocing fscanf. Fixing the format-string solved 
> my problems.
> 
> Sorry for all that noise.

I was suspicious, but my understanding of C is pretty limited (and will 
stay that way; I reckon I know enough to know its failings).

Depending on the compiler, different optimisations could also 
hide/reveal the problem.

It might be possible for the compiler to do better consistency checking, 
but that won't help where the format string is created at run-time.

-- 

Cheers
John

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