cppcheck versus a (static /dynamic) library

[Lieven de Cock]

When for example one has a project which is a static library, there could for example be in the simplest approach be 1 header file and 1 implementation file.

Again stripping a lot of stuff to have a pure reproduction.
Put 2 files together : foo.h and foo.cpp

foo.h

#ifndef FOO_H
#define FOO_H

namespace Foo
{

bool remount();

} // namespace Foo

#endif // FOO_H

foo.cpp

#include "foo.h"

namespace Foo
{

bool remount()
{
    return true;
}

} // namespace Foo

run cppcheck as : cppcheck --verbose --enable=all --enable=style --xml -I"." foo.*

===>

<results> Checking foo.cpp... 1/2 files checked 47% done Checking foo.h... 2/2 files checked 100% done <error file="foo.cpp" line="6" id="unusedFunction" severity="style" msg="The function 'remount' is never used."/> </results>

How can we kind of instruct cppcheck what are exported things, and as such should not be considered unused ? Having a local function in a cpp file not being used is interesting information one wants to know (note gcc 49 can spot those).

I mentioned "export", because one can see 2 levels, declared and header and implemented in cpp ==> do not complain about unused, but in a library it is possible to have a local .h/.cpp pair which is implementation detail and not export out of the library, so in there an unused (declared + implemented) is again interesting information.

I don't recall have this problem in the past (at least 1.5 year ago).

For now I only see one solution that is suppressing this , but I should already also suppress "--suppress=missingIncludeSystem" because on linux this is also generating noise otherwise since it does not seem to find the C/C++ headers.

Personally I have the feeling it is becoming a noise generator requiring a lot of suppresses ?

Please advice.

[Lieven de Cock]

the example above is a free method, but the same happens on the public classes of a (exported) class in case the implementation itself is not calling those member methods itself

==> very noisy.

[Daniel Marjamäki]

the unusedFunction checker does not work for libraries. I recommend that you don't enable this at all. I have tried to inform about this in the help screen and in the manual ... but I think it can be documented better.

I would personally recommend that you don't use --enable=all for analysis. The information messages are meant to be used for configuration, not analysis. I'd say --enable=style is better for analysis.

I also ignore "missingIncludeSystem" most of the time. except if there is some particular 3rd party library I want to include.

run cppcheck as : cppcheck --verbose --enable=all --enable=style --xml -I"." foo.*

you should not check headers like this. you are telling cppcheck to create a translation unit based on foo.h and check it. you can get for instance false positives. since foo.h is included by foo.cpp, foo.h is analysed properly when foo.cpp is analysed.