Re: [fltk.general] How to do realtime data display in FLTK - Forums

Thank you for the comment. I agree the "theory mode" is better. In fact I tried to make the vector a static member of Fl_Gauge but again it did not work - size() returned zero in timer callback. In the end I took Ian's suggestion: made a huge static array inside Fl_Gauge class, and a static int to count the number elements.

For the vector, I tried

1. extern variable

2. typedef first, then extern

3. class member of Gauges window (which contains all the Fl_Gauge objects)

4. static member of Fl_Gauge

Only 3. worked, as if the vector doesn't like to be a global variable. However I tried a small test program that uses a few lines of code to test a vector of int type as extern variable. That worked fine. I surrender.

On Sun, Jul 14, 2013 at 8:51 AM, Albrecht Schlosser <albrechts.fltk@gmail.com> wrote:

On 12.07.2013 22:04, Team Prii wrote:

For now I moved the vector inside the "Gauges" window (as a class
member) and that seems to work. The only complaint is that now Fl_Gauge
has to know about the "Gauges" window to access the vector, forcing
another header file to be added in Fl_Gauge.cxx. Maybe I should try to
make the vector a static member of the Fl_Gauge class instead.

<theory mode on>

In theory you would try to avoid any references to an array or vector (that resides) outside the class within the Fl_Gauges class itself. The class should deal only with its own properties. Then you would access the array/vector only outside the Fl_Gauges class, for instance like this:

Fl_Gauge g1 = new Fl_Gauge(...);
gauges[n_gauges++] = g1;
...

where gauges[] is the array and n_gauges the element counter (replace array with vector, if you like).

<theory mode off>

Of course you can add anything to your class in your application, if you decide that this is what you need, but for code reusability of the Fl_Gauges class the "theory mode" approach would be "better".

Albrecht

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