Re: sending data over udp

[Alexander Burger]

Hi Dan,

 must now use UDP and it appears that UDP simply sends PicoLisp data
 structures.

Yes, that's true. I sends a single Lisp data item (number, symbol, or
list).


 Prior to this, I was simply creating a list of byte-sized numbers and
 using wr to send them via TCP.
 
 Is there any way to do something similar using UDP?

You mean, for example, by sending a list of numbers representing bytes?
e.g.

   (udp Host Port (1 2 3 4 5 6 7))


 By the way, this question is somewhat time sensitive.

In the sense of urgency, or runtime speed? ;-)

Cheers,
- Alex
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Re: sending data over udp

[Alexander Burger]

Hi Dan,

  You mean, for example, by sending a list of numbers representing bytes?
  e.g.
 
  =A0 (udp Host Port (1 2 3 4 5 6 7))
 
 Yes, but without the extra bytes for the list data structure.

Unfortunately, the existing 'udp' function cannot do that. It can handle
only Lisp data.

You could make your own custom function, e.g. with inline-C using 'gcc'

   (load @lib/gcc.l)

   (gcc net NIL 'rawUdp)

   any rawUdp(any ex) {
  ...
  byte buf[UDPMAX];

  ...
  fill 'buf' with bytes
  sd = socket(AF_INET, SOCK_DGRAM, 0)
  sendto(sd, buf, ...)
  close(sd);
  
   }
   /**/

but this is rather tedious, manipulating the buffer and byte data.

I don't know any really easy way at the moment. How about writing raw
bytes to a pipe or temp file, and using an external tool like 'nc' to
actually transfer the data?

Cheers,
- Alex
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Re: sending data over udp

[Daniel Elliott]

Thank you for the answer and the suggestions.  I will look into them furthe=
r.

- dan

On Sat, Aug 14, 2010 at 11:28 AM, Alexander Burger a...@software-lab.de wr=
ote:
 Hi Dan,

  You mean, for example, by sending a list of numbers representing bytes=
?
  e.g.
 
  =3DA0 (udp Host Port (1 2 3 4 5 6 7))

 Yes, but without the extra bytes for the list data structure.

 Unfortunately, the existing 'udp' function cannot do that. It can handle
 only Lisp data.

 You could make your own custom function, e.g. with inline-C using 'gcc'

 =A0 (load @lib/gcc.l)

 =A0 (gcc net NIL 'rawUdp)

 =A0 any rawUdp(any ex) {
 =A0 =A0 =A0...
 =A0 =A0 =A0byte buf[UDPMAX];

 =A0 =A0 =A0...
 =A0 =A0 =A0fill 'buf' with bytes
 =A0 =A0 =A0sd =3D socket(AF_INET, SOCK_DGRAM, 0)
 =A0 =A0 =A0sendto(sd, buf, ...)
 =A0 =A0 =A0close(sd);

 =A0 }
 =A0 /**/

 but this is rather tedious, manipulating the buffer and byte data.

 I don't know any really easy way at the moment. How about writing raw
 bytes to a pipe or temp file, and using an external tool like 'nc' to
 actually transfer the data?

 Cheers,
 - Alex
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Re: sending data over udp

[Alexander Burger]

 On Sat, Aug 14, 2010 at 11:28 AM, Alexander Burger a...@software-lab.de wr=
 ote:
  You could make your own custom function, e.g. with inline-C using 'gcc'
 
  =A0 (load @lib/gcc.l)
 
  =A0 (gcc net NIL 'rawUdp)
 
  =A0 any rawUdp(any ex) {
  =A0 =A0 =A0...
  =A0 =A0 =A0byte buf[UDPMAX];

You could look at misc/crc.l which does similar things, taking a byte
count and a list of byte arguments:

   $ ./dbg misc/crc.l
   : (crc 9 (1 2 3 4 5 6 7 8 9))
   - 16900

Cheers,
- Alex
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sending data over udp

[Daniel Elliott]

A few weeks ago I asked about sending data over TCP.  Well, my program
must now use UDP and it appears that UDP simply sends PicoLisp data
structures.

Prior to this, I was simply creating a list of byte-sized numbers and
using wr to send them via TCP.

Is there any way to do something similar using UDP?

By the way, this question is somewhat time sensitive.

Thank you.

- dan
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