Thanks Guy.  That's fine by me.  I was just looking for clarificatiion.

Best regards...Paul


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-------- Original message --------
From: Guy Harris
Date:11/06/2016 01:18 (GMT+00:00)
To: Developer support list for Wireshark
Subject: Re: [Wireshark-dev] PCAP-NG Block Formats

On Jun 10, 2016, at 4:09 PM, Guy Harris <[email protected]> wrote:

> The spec should discuss that more, including emphasizing that a reader must 
> pay attention to the block total length when processing options - or deciding 
> whether there are any options to process.  I'll look at doing that.

OK, the spec now says

        All the block bodies MAY embed optional fields.  Optional fields can be 
used to insert some information that may be useful when reading data, but that 
is not really needed for packet processing. Therefore, each tool can either 
read the content of the optional fields (if any), or skip some of them or even 
all at once.

        Skipping all the optional fields at once is straightforward because 
most of the blocks are made of a first part with fixed format, and a second 
optional part. Therefore, the Block Length field (present in the General Block 
Structure, see Section 3.1) can be used to determine how many bytes of optional 
fields, if any, are present in the block. That value can be used to determine 
whether the block has optional fields (if it is zero, there are no optional 
fields), to check, when processing optional fields, whether any optional fields 
remain, and to skip all the optional fields.
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