prashanth joshi wrote:
So length-2 bytes of data is added in to tree ,starting from the
location number ofset + 5 of tvb.
My query is : is it absolutely necessary to have hf_gtp_ext_
as the second argument when ever we want to add an item?
Can not we do away with it by having a NULL as second argument instead?
No.
For one thing, the second argument is an integer value, not a pointer,
so NULL doesn't make sense as the second argument.
Furthermore, proto_tree_add_item() adds an instance of a named field, so
you *have* to supply an integer value that identifies a named field.
( I found it difficult to understand how the contents of the
proto_register_gtp array are built)
And what would be the limitations if we try to add an item using the
proto_tree_add_text( ) instead ?
Well, one limitation is that you will not be able to do any display
filtering on the value - it'll just be entered as text to be displayed.
You won't be able to select packets with a particular value of that
field by doing "gtp.ext_val == <value>".
