[PD] [comport]: 'info' not too helpful

Martin Peach martin.peach at sympatico.ca
Tue Nov 13 20:20:01 CET 2007

Roman Haefeli wrote:
>On Mon, 2007-11-12 at 18:36 +0000, Martin Peach wrote:
> > Roman Haefeli wrote:
> > >
> > >hi all
> > >
> > >when sending 'info' to comport, it outputs a bunch of messages to its
> > >right outlet to give you some information about the properties of the
> > >connection. however, if you use 'devicename <something>' to open a
> > >connection, 'info' tells you 'port 9999', which is of course wrong. 
> > >you do 'open 9999', not the same device gets opened, or more likely: no
> > >device gets openend at all.
> >
> > 9999 is just a placeholder to indicate that the device was opened by 
> > On Windows the correct index is given because all the ports are named 
> > On linux and OSX they have more complex names and glob is used to 
>generate a
> > list of all ports and the index is just the order in the list. I can add
> > that feature soon...

It's now implemented. You can open a port by name, like [devicename 
/dev/ttyS0(, and the [info( message will give the index.

> >
> > Until then, in recent [comport]s you can send the [ports( message and 
>get a
> > list on the status outlet.
> > For example:
> > [ports(
> > |
> > [comport]
> > |          |
> >           [route ports]
> >            |
> >           [unpack 0 s]
> > gives you pairs of index and name, which you could compare with the name 
> > opened the port with to find the index.
> >
> > >
> > >i am working on a bunch of arduino abstractions that do find
> > >automagically the correct port of the arduino board. i decided to use
> > >different approaches on different os to probe the port of arduino. i
> > >experienced, that on linux the arduino sometimes appears on port 8,
> > >sometimes on port 48, probably it is different again on other linux
> > >flavors. in order to avoid 40 or more error messages before the correct
> > >port is found, i probe not with 'port [1-99]', but with
> > >'devicename /dev/ttyUSB[0-20]' on linux, since the devicename seems to
> > >be consistent throughout all linux flavors. however, i would like to
> > >avoid, that several abstractions use all their own [comport] on the 
> > >port, since i encountered, that when several [comport]s are listening 
> > >the same port, not all [comport]s will always receive all messages. for
> > >all above reason i would need to know, what the actual port number is 
> > >a connection, even if the connection was opened using
> > >'devicename /dev/ttyUSB[0-20]'.
> >
> > It might be better to use only one [comport] and send the data to the
> > abstractions with [send] and [receive] since normally opening a comport 
> > fail to open a port if the same port is already in use.
>yo, sorry, if my sentences have been too confusing, but this is exactly
>what i would like to achieve. i encountered, that it _is_ possible to
>run several [comport]s on the same port, but then sometimes data from
>the arduino board doesn't seem to reach all [comport] objects. that is
>why i would like to implement a kind of a singleton pattern, that
>automatically uses the already existing/connected [comport], if there is
>any and otherwise uses it's on [comport]. in order to achieve that, i
>need to know the port number, that a certain [comport] uses. this is
>very easy, if the connection was opened using a 'open' message, but if a
>certain [comport] established a connection using the 'devicename'
>method, then i don't know, which port this [comport] actually is using.
>yo, what i am going to try now is to work with the 'port' method, as you
>proposed, so that i can find out, which device got which index (which
>actually should solve my problem)
>can you tell me, how long the new [comport] has been in cvs? is it
>probably already part of the released pd-extended-0.39.3?

The [ports( message has been there since August 2007. Today I committed a 
new version to cvs. It sets the index properly when you open a port by name. 
It won't work if the port has a really odd name that isn't something like 
/dev/tty (because I can't guess what it's name might be and it can't be 
opened with an index number anyway) so in that case it's better to make a 
symlink with a "normal" name.


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