FTBFS if "-Werror=format-security" flag is used

[Kevin Kofler]

Adam Jackson wrote:

> On Fri, 2013-12-06 at 02:21 +0100, Kevin Kofler wrote:
>  
>>     QString line;
>>     line.fill( '-', 60 );
>>     qDebug( line.ascii() );
>> As you can see, the format string being passed here is provably constant.
> 
> So fix the compiler.

I don't think GCC will ever be able to prove that it is a constant. It would 
at least have to do intermodule inlining on the linked qstring.o to do that, 
which means qt3 would have to use the LTO support. Even then, I wouldn't 
count on it. Plus, if this construct were found in application code rather 
than in qt3 itself, GCC would even have to do the intermodule inlining on 
libqt-mt, which would also have negative consequences on binary 
compatibility.

But knowing the contract of QString (Qt 3's in this case, but it's the same 
in Qt 4 and Qt 5), it's trivial for a human to prove it.

        Kevin Kofler