Question

I have two macros that declares class properties:

DECLARE_QUERY_PARAM_LONG(name)
DECLARE_QUERY_PARAM_STRING(name)

I want to count number of calls of this macros inside of my class and init

static const size_t paramsCount 

with that number like this:

class MyClass {
...

    DECLARE_QUERY_PARAM_LONG(param1)
    DECLARE_QUERY_PARAM_STRING(param2)
    DECLARE_QUERY_PARAM_STRING(param3)
    DECLARE_QUERY_PARAM_LONG(param4)

    static const size_t paramsCount = PARAMS_COUNT; // 4 in this case

...
};

Is this ever possible?

Answer 1

You can at least count number of lines in the following way:

class MyClass
{
    static const int line_1 = __LINE__;
    DECLARE_QUERY_PARAM_LONG(param1)
    DECLARE_QUERY_PARAM_STRING(param2)
    DECLARE_QUERY_PARAM_STRING(param3)
    DECLARE_QUERY_PARAM_LONG(param4)
    static const int line_2 = __LINE__;
    static const int macro_calls = line_2 - line_1 - 1;

public:
    MyClass()
    {
        cout << macro_calls << endl;
    }
};

But I think you’ll need C++11 to do that. And You cannot have empty lines within those two __LINE__s. Otherwise, you’ll have to count those empty lines as well.