Wireshark-dev: [Wireshark-dev] I need wmem_alloc advice please
From: Paul Offord <[email protected]>
Date: Thu, 15 Sep 2016 16:44:49 +0000

My porting of TRANSUM from LUA to C continues.  I now have a working dissector but I then read README.developer and noted the guidance regarding use of static buffers.  I assume this applies to arrays too and so I’m now trying to convert the statically defined arrays to versions based on dynamic memory allocation.  I’ve converted some string buffers and a simple gboolean array without problems.  I then tried to convert an array of structures and this caused crashes all over the place.


Before the conversion I had this as a global variable:




I replaced this with a global variable:


    PKT_INFO *sub_packet;


And this in my init function:


    sub_packet = (PKT_INFO *)wmem_alloc(wmem_file_scope(), (MAX_SUBPKTS_PER_PACKET * sizeof(PKT_INFO)));


I subsequently use it like this:


    sub_packet[i].frame_number = 0;


I seem to be getting memory corruption as a result of this change.  Weird things happen, like I lose preference variables.


What am I doing wrong here?


Thanks and regards…Paul


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