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Re: Question about an error with ports
From: |
Chris Vine |
Subject: |
Re: Question about an error with ports |
Date: |
Fri, 11 Mar 2022 12:05:00 +0000 |
On Thu, 10 Mar 2022 18:46:34 -0500
Olivier Dion via General Guile related discussions <guile-user@gnu.org>
wrote:
> On Thu, 10 Mar 2022, Zelphir Kaltstahl <zelphirkaltstahl@posteo.de> wrote:
>
> > Just one question: Why is get-bytevector-some better than
> > get-bytevector-n and specifying a number of bytes?
>
> I haven't check the implementation details, but I think it's just a
> question of buffering. `get-bytevector-n` will block just like
> `get-bytevector-some` when the port is empty. The former will return up
> to N bytes and the latter might return more than N bytes. The former
> probably also lead to less memory allocation since N is known in
> advanced, a singled allocation can be made, while the latter might do
> multiple allocations. This can be useful depending on your usage of the
> port. For example, you could make a web server that only accepts HTTP
> body up to 4096 bytes (1 system page). This is what some web server
> does I think.
>
> There's also `get-bytevector-all`, but this would lead to more memory
> usage and multiple allocations. Again, it depends on the usage.
Avoid using get-bytevector-n!, get-bytevector-some and
get-bytevector-all if you are going to use something like fibers or
some other asynchronous i/o, as those procedures are not suspendable
(they can block). get-bytevector-n (note the difference from
get-bytevector-n!) and get-string-all are suspendable and should
generally be preferred where suspension is required.
- Question about an error with ports, Zelphir Kaltstahl, 2022/03/09
- Re: Question about an error with ports, Olivier Dion, 2022/03/10
- Re: Question about an error with ports, Zelphir Kaltstahl, 2022/03/10
- Re: Question about an error with ports, Olivier Dion, 2022/03/10
- Re: Question about an error with ports,
Chris Vine <=
- Re: Question about an error with ports, Olivier Dion, 2022/03/11
- Re: Question about an error with ports, Chris Vine, 2022/03/11
- Re: Question about an error with ports, Olivier Dion, 2022/03/11
- Re: Question about an error with ports, Chris Vine, 2022/03/11
- Re: Question about an error with ports, Maxime Devos, 2022/03/11
- Re: Question about an error with ports, Maxime Devos, 2022/03/11
- Re: Question about an error with ports, Chris Vine, 2022/03/11
- Re: Question about an error with ports, Chris Vine, 2022/03/11
- Re: Question about an error with ports, Maxime Devos, 2022/03/11
- Re: Question about an error with ports, Olivier Dion, 2022/03/11