> Date: Wed, 13 Feb 2008 19:44:35 -0700 > From: stephentfisher@xxxxxxxxx > To: wireshark-dev@xxxxxxxxxxxxx > Subject: Re: [Wireshark-dev] How to only output certain selected segment of a packet? > > On Thu, Feb 14, 2008 at 12:09:08AM +0000, yenan wrote: > > > I am trying to output a paclet with a index field whihc is 20-bits > > long , If I use "guint32" to define the variable for "INDEX" field, > > and have the index value as "12345678", how can I chop the "678" off, > > and display only "12345" to the screen? > > First, do not reply to someone else's message and change the subject. > This causes confusion for those of us who use threaded mail readers. > Compose a new message to wireshark-dev@xxxxxxxxxxxxx instead. >
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SORRY, I DID NOT REALIZE THAT! IT SEEMS I AM WAY TOO LAZY!
> It sounds like you need to use a bitmask in the field registration (from > doc/README.developer): > > bitmask > ------- > If the field is a bitfield, then the bitmask is the mask which will > leave only the bits needed to make the field when ANDed with a value. > The proto_tree routines will calculate 'bitshift' automatically > from 'bitmask', by finding the rightmost set bit in the bitmask. > If the field is not a bitfield, then bitmask should be set to 0. > > This bitmask (in hex) would go where the 0x0 usually is in a field > registration. See epan/dissectors/packet-vnc.c for a number of examples > (such as in &hf_vnc_zrle_rle). > --------------------------------- >THANK YOU VERY MUCH FOR THE INFORMATION!!
> Steve > > > > _______________________________________________ > Wireshark-dev mailing list > Wireshark-dev@xxxxxxxxxxxxx > http://www.wireshark.org/mailman/listinfo/wireshark-dev
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