Regarding Read Only Setting in getParamImpl()

[BruceChanJianLe]

Hi everyone, I am trying to implement "Parameters On Set Parameter Callback" feature, which I can update the parameters through a callback function. However, it seems like if I use the GetParam method, the declared parameter is set to a read only state.

Is there a special reason why it is set to read only?

It is set at this line here.

filters/include/filters/filter_base.hpp

Line 134 in 5507bc5

desc.read_only = true;

If I set param through the terminal, I will get this output.

Setting parameter failed: parameter 'filter1.params.output_frame' cannot be set because it is read-only

[jonbinney]

Sorry for not responding to this earlier, but this should get resolved through #83

[BruceChanJianLe]

Hey @jonbinney thanks for getting back!
I had worked around this issue since then but glad to see that someone has finally taken a look into this matter.

[jonbinney]

The fix isn't merged yet, so I'll leave this open until it is :-)