Re: does char *str="abcd"; alloc addressable memory?

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From	Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups	comp.lang.c
Subject	Re: does char *str="abcd"; alloc addressable memory?
Date	Mon, 24 Aug 2020 17:04:36 -0700
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Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:

> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>
>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>>
>>> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>>>
>>>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>>>> [...]
>>>>
>>>>> Much more recently than that, gcc had an option -fwriteable-strings.
>>>>> That option has since been removed, but it was still available in
>>>>> the last ten years or so.
>>>>
>>>> The "-fwritable-strings" option (note spelling),
>>>
>>> Right.  Either the option was misspelled in one of the sources I
>>> found, or I made a mistake in copying it.  Either way thank you
>>> for the followup.
>>>
>>>> was removed in 2004.
>>>> The version string for the commit that removed it was
>>>> "3.5.0 20040223 (experimental)".
>>>
>>> If the first commit was to an experimental version in 2004, the
>>> feature would still be available in production releases for at
>>> least several years, and probably more than that considering
>>> delays in upgrading distributions, etc.  In any case it's still
>>> a lot more recent than the 1980s, and even after C99 was done.
>>
>> I think gcc just adds "(experimental)" to the version string for
>> any non-released version.  The change would have been part of gcc
>> release 3.5.0 if it had existed.
>>
>> The "-fwritable-strings" option was deprecated starting in release
>> 3.4.0 (committed 2004-04-19) and removed starting in release 4.0.0
>> (committed 2005-04-21).  The most recent release that supported
>> the option was 3.4.6 (committed 2006-03-06).  (The oldest version
>> of gcc I currently have access to is 4.1.2.)
>>
>> I'm sure it took several years before distributions stopped
>> supporting gcc 3.X, but I don't have data on that.
>
> More background:  This is from the manual for gcc 3.4.6:
>
>     @item -fwritable-strings
>     @opindex fwritable-strings
>     Store string constants in the writable data segment and don't uniquize
>     them.  This is for compatibility with old programs which assume they can
>     write into string constants.
>
>     Writing into string constants is a very bad idea;  ``constants'' should
>     be constant.
>
>     This option is deprecated.
>     @end table

Sounds right.  And except for the misspelling, which I already
acknowledged, all consistent with what I said earlier.

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Re: does char *str="abcd"; alloc addressable memory? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2020-08-24 17:04 -0700

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