From: Maxime Devos <maximedevos@telenet.be>
To: Damien Mattei <damien.mattei@gmail.com>,
guile-user <guile-user@gnu.org>,
guile-devel <guile-devel@gnu.org>
Subject: Re: string is read-only
Date: Wed, 3 Aug 2022 11:41:47 +0200 [thread overview]
Message-ID: <8294f792-cdb6-46a4-899a-f0a23e67b249@telenet.be> (raw)
In-Reply-To: <CADEOade_rTYJB0+QzgNVkK=x2khp0hgjySo_hUp+1dpJdPgrWg@mail.gmail.com>
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On 03-08-2022 11:12, Damien Mattei wrote:
> scheme@(guile-user)> (define str2 "hello")
> scheme@(guile-user)> (string-set! str2 4 #\a)
> ice-9/boot-9.scm:1669:16: In procedure raise-exception:
> string is read-only: "hello"
It's not -- the existence of read-only strings is implied by
substring/read-only, and also see:
> (guile)Object File format
> Typically all segments of an ELF file are marked as read-only, except
> that part that represents modifiable static data or static data that
> needs load-time initialization. Loading an ELF file is as simple as
> mmapping the thing into memory with read-only permissions, then using
> the segment table to mark a small sub-region of the file as writable.
> This writable section is typically added to the root set of the garbage
> collector as well.
I'm not aware of explicit documentation that string literals may not be
modified (and in this case, cannot be modified). However, see the
following mail on string mutability and program text:
https://lists.gnu.org/archive/html/guile-devel/2012-01/msg00135.html
and maybe surrounding definitions.
Greetings,
Maxime.
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next prev parent reply other threads:[~2022-08-03 9:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-03 9:12 string is read-only Damien Mattei
2022-08-03 9:32 ` Thomas Morley
[not found] ` <CADEOadctjXAyZfwYG3Qbky129i0NBbM+HK6g1iUwvA_HrT4UxA@mail.gmail.com>
2022-08-03 9:51 ` Fwd: " Damien Mattei
2022-08-03 9:59 ` Maxime Devos
2022-08-03 9:41 ` Maxime Devos [this message]
2022-08-03 9:57 ` Ricardo G. Herdt
2022-08-03 10:55 ` Damien Mattei
2022-08-03 10:59 ` Maxime Devos
2022-08-03 11:34 ` Damien Mattei
2022-08-03 9:42 ` Taylan Kammer
2022-08-03 9:50 ` Jean Abou Samra
2022-08-03 10:30 ` Taylan Kammer
2022-08-03 10:33 ` Jean Abou Samra
-- strict thread matches above, loose matches on Subject: below --
2022-08-03 11:55 Pierpaolo Bernardi
2022-08-03 12:48 ` Damien Mattei
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