Wireshark-dev: Re: [Wireshark-dev] Wireshark col_append_sep_str function
From: "Peimann, Jannis" <[email protected]>
Date: Fri, 3 Apr 2020 11:22:46 +0000


thanks for your help.

The solution from Graham Bloice was the one I was looking for.

I have to use col_set_fence.


Now I just have to find a good solution for the prepend pdu_conti_NAME_LONG every time it is called.

Because this thing should only be once in the Info column and not for every PDU.


proto_pdu_conti = proto_register_protocol(pdu_conti_NAME_LONG, pdu_conti_NAME, pdu_conti_NAME_FILTER);



Now it is like:

GeneralInfo, PDU1, GeneralInfo, PDU2…

Should be like GeneralInfo PDU1, PDU2…


Thanks for your help guys.



Mit freundlichen Grüßen/Best regards,


Jannis Peimann



Von: Wireshark-dev <[email protected]> Im Auftrag von Pascal Quantin
Gesendet: Freitag, 3. April 2020 11:40
An: Developer support list for Wireshark <[email protected]>
Betreff: Re: [Wireshark-dev] Wireshark col_append_sep_str function


Hi Jannis,


Le ven. 3 avr. 2020 à 11:22, Peimann, Jannis <[email protected]> a écrit :

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?


Are you sure you are not calling col_clear(pinfo->cinfo, COL_INFO) somewhere in your code?


Best regards,