fix dangling references and add gcc13 compability

[mathisloge]

enumDslObj() and dslObj() returns a new object, which goes out of scope after the assignment. Therefore there are dangling references after the assignments.

the cstdint is required for gcc13

[arobenko]

Hi Mathis, Sorry, you're wrong here, the places you're trying to fix are NOT dangling references. I must reject this pull request.

Details:

• The XML parsing is performed using commsdsl::parse::Protocol class. Note, that it is REAL pImpl idiom, while holding the implementation by std::unique_ptr.
• The implementation classes such as commsdsl::parse::MessageImpl are owned and held by the commsdsl::parse::ProtocolImpl.
• The commsdsl::parse::Message is a wrapper around pointer to the commsdsl::parse::MessageImpl.
• Even if the commsdsl::parse::Message is a temporary object, it abstracts away an access to some other data structures held by the commsdsl::parse::MessageImpl.
• As the result it's safe to acquire and retain references to inner data structures.
• The changes you proposed will force unnecessary copying of lists and maps, which don't get destroyed when the temporary object gets destructed.

[arobenko]

Thanks for the report of missing <cstdint> though. I've added it in several other places on "develop" branch.

[mathisloge]

Hi Alex,

thanks for pointing that out. Due to the similar names of the classes I have not noticed the differences in the datatypes of mPimpl in the different Message types.

But then we still need to fix some false positive dangling reference compiler warnings. Currently it won't compile with gcc13. Should I wrap the calls here in

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdangling-reference"
<code>
#pragma GCC diagnostic pop

[arobenko]

Unfortunately I don't have gcc-13 on my Linux environment and I'm a bit reluctant to configure docker with newer system versions to try and test it. I suggest adding an extra condition somewhere here:

if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "13.0")
    list (APPEND extra_flags_list "-Wno-dangling-reference")
endif () 

Try it and let me know (or submit a pull request) if it works.