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bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered por
From: |
Andy Wingo |
Subject: |
bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports |
Date: |
Fri, 12 Jan 2018 11:33:32 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) |
On Fri 12 Jan 2018 11:15, address@hidden (Ludovic Courtès) writes:
> Andy Wingo <address@hidden> skribis:
>
>> On Thu 11 Jan 2018 22:55, Mark H Weaver <address@hidden> writes:
>
> [...]
>
>>>>> Out of curiosity, is there a reason why you're using an unbuffered port
>>>>> in your use case?
>>>>
>>>> It’s to implement redirect à la socat:
>>>>
>>>>
>>>> https://git.savannah.gnu.org/cgit/guix.git/commit/?id=17af5d51de7c40756a4a39d336f81681de2ba447
>>>
>>> Why is an unbuffered port being used here? Can we change it to a
>>> buffered port?
>>
>> This was also a question I had! If you make it a buffered port at 4096
>> bytes (for example), then get-bytevector-some works exactly like you
>> want it to, no?
>
> It might work, but that’s more by chance no?
No, it is reliable. get-bytevector-some on a buffered port must either
return all the buffered bytes or perform exactly one read (up to the
buffer size) and either return those bytes or EOF. As far as I
understand, that is exactly what you want.
Using buffered ports has two additional advantages: you get to specify
the read size, and returned bytevectors can be allocated to precisely
the right size (no need to overallocate then truncate).
Andy
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, (continued)
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Ludovic Courtès, 2018/01/11
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Mark H Weaver, 2018/01/11
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Ludovic Courtès, 2018/01/11
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Mark H Weaver, 2018/01/11
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Andy Wingo, 2018/01/12
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Ludovic Courtès, 2018/01/12
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports,
Andy Wingo <=
- bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports, Ludovic Courtès, 2018/01/13