CODEWITHSUNDEEP
c++cinstance-variables
user402642
user402642

Reputation:

C/C++ Possible to get a "list" of instance members by querying a class?

Suppose we have a struct in C++:

struct foobar
{
      int age; 
      bool hot;
      String name
};

Is there a way, programatically, to query the above struct to extract its instance members? For example:

String[] members = magicClass.getInstanceMembers(foobar);

Members would have ["age", "hot", "name"] as it's values.

Possible? The reason why I ask is because I have structs that change over time (variables added/removed). I want to be able to create auto-generating Lua files with this saved data.

Thanks

Upvotes: 18

Views: 7187

Answers (3)

dmckee --- ex-moderator kitten
dmckee --- ex-moderator kitten

Reputation: 101181

If you really, really want to write "c++" code with reflection you can look at what ROOT does with cint and the makecint code-generator. But this probably isn't what you really want to do...

Upvotes: 1

Charles Salvia
Charles Salvia

Reputation: 53299

No, standard C++ doesn't support that type of reflection. There are some "hacky" ways using macros to create a type-traits-esque template that will use SFINAE to statically determine whether or not a particular class has a certain data member or member function, but nothing that will actually enumerate every member of a class.

In fact, C++ was designed with a certain philosophy in mind that would make it difficult, if not counter-productive, to support the type of runtime reflection we see in higher-level languages like C#/Java. See Why does C++ not have reflection? for a thorough discussion on this issue.

Upvotes: 14

Marcin
Marcin

Reputation: 12600

I think what you're looking for is called Reflection. This is not easy to do in C / C++: http://www.garret.ru/cppreflection/docs/reflect.html http://en.wikipedia.org/wiki/Reflection_(computer_science)

Upvotes: 1

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