Re: [9fans] Re: echo -n - Plan9

This is a discussion on Re: [9fans] Re: echo -n - Plan9 ; On Nov 21, 2006, at 5:32 PM, dmr@plan9.bell-labs.com wrote: > 8th edition streams began to transmit them > over pipes (or networks). Since this thread started I've been nagged by the memory of UUCP's 'e' protocol. If my brain hasn't ...

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Thread: Re: [9fans] Re: echo -n

  1. Re: [9fans] Re: echo -n

    On Nov 21, 2006, at 5:32 PM, dmr@plan9.bell-labs.com wrote:

    > 8th edition streams began to transmit them
    > over pipes (or networks).


    Since this thread started I've been nagged by the memory of UUCP's
    'e' protocol. If my brain hasn't completely cached out, 'e' used the
    ability of Datakit to preserve 0-length messages as an inband
    delimiter, vs. the 't' protocols use of explicit protocol field
    length counters. (Or was it 'x' that used null read/write ops ... ?)

    --lyndon

  2. Re: [9fans] Re: echo -n

    0 is a number ... a fine and useful one. if you want to ignore echo
    then SYSCALL(1) will do exactly what you want.

    brucee

    On 11/24/06, Lyndon Nerenberg wrote:
    > On Nov 21, 2006, at 5:32 PM, dmr@plan9.bell-labs.com wrote:
    >
    > > 8th edition streams began to transmit them
    > > over pipes (or networks).

    >
    > Since this thread started I've been nagged by the memory of UUCP's
    > 'e' protocol. If my brain hasn't completely cached out, 'e' used the
    > ability of Datakit to preserve 0-length messages as an inband
    > delimiter, vs. the 't' protocols use of explicit protocol field
    > length counters. (Or was it 'x' that used null read/write ops ... ?)
    >
    > --lyndon
    >


  3. Re: [9fans] Re: echo -n

    I just browsed the Plan 9 source, and the reason for the 0-byte write is
    that Plan9 echo doesn't used a buffer I/O subsystem such as stdio,
    but instead allocates one big array via malloc, copies the arguments
    etc. into it, and dumps the whole thing in a single write call. That makes
    it dependent on malloc finding enough memory, unlike most other
    implementations; however, it does guarantee that if it works at all,
    all the argumens were written together in a single record. I don't know
    if anything depends on that property, but it seems rather fragile..

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