We're now a non-profit! Support open source packet analysis by making a donation.

Wireshark-dev: Re: [Wireshark-dev] Wireshark col_append_sep_str function

From: Graham Bloice <graham.bloice@xxxxxxxxxxxxx>
Date: Fri, 3 Apr 2020 10:28:57 +0100

On Fri, 3 Apr 2020 at 10:22, Peimann, Jannis <jannis.peimann@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Hi together,


I want to add information to the Info column for every frame in Wireshark.

This is working fine as long as I only have one PDU in my UDP package.

If I  have more than one PDU, then it overwrites the old Info column string. It is not appending.


This is my function:

if (pdu_description != NULL)


col_append_sep_str(pinfo->cinfo, COL_INFO, ",", pdu_description);                        

g_print("Debug Message: frame number [%d] [%s]\n", pinfo->fd->num, pdu_description);/*Debug Console Message */



This col_append_sep_str function is from column-utils.c

For example the DEBUG Message is called twice, if I have two PDUs. This is working.



Right now I only have this:

PDU Protocol, Name2

But it should be:

PDU Protocol, Name1, Name2…


I think there is a problem with losing the old frame information, because it is writing again PDU Protocol.

Do you guys know what I’m missing?


Thanks for your help.



Mit freundlichen Grüßen/Best regards,


Jannis Peimann

Look for col_set_fence in README.dissector

Graham Bloice