Hi Drew and Zoli, Am Sun, 8 Dec 2019 17:51:12 +0100 schrieb Csahok Zoltan <ha5...@freemail.hu>:
> Hi Drew, > > Trailing zero and newline have most likely historical origin. > > The zero was introduced abt 9 years ago in this commit: > https://github.com/Tlf/tlf/commit/5a2be34d01b296bc8b8d8b362407cc3077e3c6d8#diff-8be0c8c50997da170641d3392ba81b5a At that time it was unclear if cwdaemon needed a the send message as a zero terminated string or not, so I added it to be sure. Actual it seems that it is not needed. We can revert that commit. 73, de Tom > Apparently cwdaemon needed it. Now it does not for sure, neither any > newline. It actually removes NL: > https://github.com/acerion/cwdaemon/blob/master/src/cwdaemon.c > (line 1140) > > winkeydaemon as a defensive measure silently ignores non-processable > characters. Probably cwdaemon (libcw) does the same. > > Technically the trailing NL is a result of not chopping it after > fgets(). While for CW it is irrelevant, it might make sense for > digital modes. Not sure, though, as digital keyer code could add NL > on its own. > > So all in all I think we could get rid of both trailing chars without > issues. > > 73, > Zoli > > > On Sat, Dec 07, 2019 at 04:35:28PM +0000, Drew Arnett wrote: > > Doing some debugging and cleanup of my pywinkerdaemon implementation > > of cwdaemon. (I introduced some bugs with recent feature > > introduction.) > > > > A few years ago, I looked at the UDP packets several different > > cwdaemon clients sent. Some, like TLF, send a single trailing null > > character which is not needed. Some sent quite a lot. (Allocated a > > max UDP data structure, wrote nulls, then wrote the message to the > > beginning. Still, should have not bothered transmitting all that > > padding.) > > > > Looking at tlf as included in debian 10.2 today, I see it also has a > > \n (0x0a) character between the end of the CW message and the single > > null character. > > > > I recommend that tlf doesn't transmit either the 0x0a or the 0x00 > > trailing characters. Unless this would break other independent > > cwdaemon implementations. Anybody know? > > > > Best regards, > > > > Drew > > n7da -- "Do what is needful!" Ursula LeGuin: Earthsea --
