library configuration: argument type / output parameter

[Daniel Marjamäki]

It would help Cppcheck ValueFlow analysis if it knows if a function parameter is an "output" parameter.

Example code:

    int x = 0;
    dostuff(x); // <- is x changed by dostuff?
    return y / x; // <- is this a division by zero?

What do you think? Should we add "argument type" information or just some <input> or <output> element?

[Daniel Marjamäki]

My spontanous feeling is that we can add <output> now for this purpose. And then full "argument type" information later to make it possible to configure overloaded functions.

I would be interested to hear what you think..

[orbitcowboy]

Good idea: How about <arg nr="1" direction="in"/> for input. Output could be direction="out" and input and output arguments could be configured as direction="inout"?

[Daniel Marjamäki]

Thanks for your feedback. Since you are very active, I want to know what your preference is.

[orbitcowboy]

I prefer my solution because it is more compact. But it is no showstopper if your suggestion is implemented :-)

[versat]

+1 for first adding the possibility to specify if it is an input and / or output argument.

I have no preference for a concrete syntax.
If i can help for example with enhancing the relaxng file i am glad to hear what to do. I plan to work further on it anyway.

[Daniel Marjamäki]

If i can help for example with enhancing the relaxng file i am glad to hear what to do. I plan to work further on it anyway.

Feel free to implement the suggestion made by orbitcowboy. Is it ok if you:
- fix the relaxng file
- Add a variable (enum) in our Library
- Fix the Library load function.

?

After that we can look at using this info in the analysis. Feel free to adjust the isVariableChangedByFunctionCall().

[Daniel Marjamäki]

I would be very happy to delegate all this to you :-)

[versat]

Ok. If you can wait until tomorrow i will try to implement it. Not sure about the last part because i have not looked at this function but i will see 😀
If someone wants to implement it now i have no problem with that also.

[Daniel Marjamäki]

Great.. I can wait until tomorrow. Let me know if I can help you with the isVariableChangedByFunctionCall(). A hint: if there is library configuration then I do not think it's necessary to set the "inconclusive" flag.