Clean up handling of --capture-comment.

Don't store the comments in a capture_options structure, because that's
available only if we're being built with capture support, and
--capture-comment can be used in TShark when reading a capture file and
writing another capture file, with no live capture taking place.

This means we don't handle that option in capture_opts_add_opt(); handle
it in the programs that support it.

Support writing multiple comments in dumpcap when capturing.

These changes also fix builds without pcap, and makes --capture-comment
work in Wireshark when a capture is started from the command line with
-k.

Update the help messages to indicate that --capture-comment adds a
capture comment, it doesn't change any comment (much less "the" comment,
as there isn't necessarily a single comment).

Update the man pages:

- not to presume that only pcapng files support file comments (even if
that's true now, it might not be true in the future);
- to note that multiple instances of --capture-comment are supported,
and that multiple comments will be written, whether capturing or reading
one file and writing another;
- clarify that Wireshark doesn't *discard* SHB comments other than the
first one, even though it only displays the first one;

4 files changed, 21 insertions, 15 deletions

diff --git a/doc/dumpcap.pod b/doc/dumpcap.pod
index 19d16c5dfd..c5f043f44c 100644
--- a/doc/dumpcap.pod
+++ b/doc/dumpcap.pod
@@ -419,11 +419,14 @@ the default capture link type is used if provided.
 
 =item --capture-comment  E<lt>commentE<gt>
 
-Add a capture comment to the output file.
+Add a capture comment to the output file, if supported by the output
+file format.
 
 This option is only available if we output the captured packets to a
-single file in pcapng format. Only one capture comment may be set per
-output file.
+single file.
+
+This option may be specified multiple times.  Note that Wireshark
+currently only displays the first comment of a capture file.
 
 =item --list-time-stamp-types
 
diff --git a/doc/editcap.pod b/doc/editcap.pod
index 1d7f520e1e..cf8bcb5f16 100644
--- a/doc/editcap.pod
+++ b/doc/editcap.pod
@@ -375,12 +375,12 @@ the same command line.
 
 =item --capture-comment E<lt>commentE<gt>
 
-Adds the given comment to the Section Header Block (SHB) of the pcapng
-output file. New comments will be added I<after> any comments present in the
-input file unless B<--discard-capture-comment> is also specified.
+Adds the given comment to the output file, if supported by the output
+file format.  New comments will be added I<after> any comments present
+in the input file unless B<--discard-capture-comment> is also specified.
 
-This option may be specified multiple times. Note that Wireshark currently only
-recognizes the first comment of a capture file.
+This option may be specified multiple times.  Note that Wireshark
+currently only displays the first comment of a capture file.
 
 =item --discard-capture-comment
 
diff --git a/doc/tshark.pod b/doc/tshark.pod
index 5548b1a971..e0059d43cf 100644
--- a/doc/tshark.pod
+++ b/doc/tshark.pod
@@ -1728,13 +1728,11 @@ SMB packets exchanged by the host at IP address 1.2.3.4 .
 
 =item --capture-comment E<lt>commentE<gt>
 
-Add a capture comment to the output file.
+Add a capture comment to the output file, if supported by the output
+file format.
 
-This option is only available if a new output file in pcapng format is
-created.
-
-This option may be specified multiple times. Note that Wireshark currently only
-recognizes the first comment of a capture file.
+This option may be specified multiple times.  Note that Wireshark
+currently only displays the first comment of a capture file.
 
 =item --list-time-stamp-types
 
diff --git a/doc/wireshark.pod b/doc/wireshark.pod
index c94814901a..f9b91b19b3 100644
--- a/doc/wireshark.pod
+++ b/doc/wireshark.pod
@@ -319,7 +319,12 @@ Start with the given configuration profile.
 
 =item --capture-comment E<lt>commentE<gt>
 
-Set the capture file comment, if supported by the capture format.
+When performing a capture file from the command line, with the B<-k>
+flag, add a capture comment to the output file, if supported by the
+capture format.
+
+This option may be specified multiple times.  Note that Wireshark
+currently only displays the first comment of a capture file.
 
 =item -d  E<lt>layer typeE<gt>==E<lt>selectorE<gt>,E<lt>decode-as protocolE<gt>