Qt compilations are triggering quite a number of warnings independent of the compiler used. Most people choose to ignore them. Typically they do not cause any harm.

Why is it so important for you to switch off these warnings?

These warnings are not from a Qt compilation. This is a 3rd party library project which my project is depend on it.

A source code on this library generates thousands of warnings. I don’t want to see these warnings while compiling my project. I disabled these warnings in MSVC compiler using these lines in that library pro file:

Now i need to port my project to Mac OS X Lion. And i cannot suppress these warnings.

@koahnig: The fact that Qt triggers a lot of warnings is actually quite annoying. From a code quality perspective, warnings have a urgency similar to errors, IMO. Often the only warnings that are impossible to get rid off are the ones generated by Qt itself.

If possible at all: warnings should be fixed instead of ignored. Seriously. If you are not going to use a variable, be explicit about and either:

1. remove the argument completely from the function, or
2. remove the name of the argument from the function, or
3. use a construct like Q_UNUSED(myVariable) to be explicit about you not using the argument.

But don’t just ignore the warning. Warnings are there for a reason. The may point to more severe issues or may develop into real problems later on.

Thanks for the info but I already know these rule of thumbs. I actually follow these rules. But this is not my project. This is a third party library and i’m not allowed to edit these library’s source code. It’s library writer’s responsibility. I just want to suppress these warnings by editing pro file.

In gcc

Any suggestions?

miroslav wrote:

@koahnig: The fact that Qt triggers a lot of warnings is actually quite annoying. From a code quality perspective, warnings have a urgency similar to errors, IMO. Often the only warnings that are impossible to get rid off are the ones generated by Qt itself.

Yes, I agree completely. The first time I was compiling Qt libs it was a shock to me when seeing the warnings. However, I (have) arranged myself with it.

I am certainly agreeing also with Andre. He is summarizing my coding ethics.

My answer was refering to the compilation of the Qt libs.

On the other hand I find it more than a bit annoying that I have to clatter my code with pragmas for ignoring warnings when a Qt header is included. IMHO that is a nogo, but on an individual basis you are fighting against windmills there.

Agreed. I do understand that it is hard to make sure no warnings are issued by any compiler. The issue could get a bit more focus, though.

Here’s my console output for an unexpected warning generation:

As you can see i passed -Wno-unused-variable parameter but clang++ still generates unused-variable error.

Just poking in the dark. But I have noticed that there is a -Wall after -Wno-unused-variable.
Could it be that you switching off the warning and switching it on with -Wall ?
I do not know this compiler.

Oh! Yes that’s what i’m missing. @koahnig Thank you very much. I should avoid using warn_on CONFIG directive.