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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: does char *str="abcd"; alloc addressable memory?
Date: Mon, 06 Jul 2020 12:20:07 -0700
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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
> Malcolm McLean <malcolm.arthur.mclean@gmail.com> writes:
>> On Monday, 6 July 2020 12:57:06 UTC+1, Bonita Montero  wrote:
>>> The compiler should give you an error for casting a string-literal to
>>> a pointer to non-const characters. If cou cast it explicitly you may
>>> modify the caracters and that usually works, but it's not guaranteeed.
>>> Most platforms will make a writable copy of a read-only mapped page.
>>>
>> It doesn't warn because const was a late addition to C, and string literals
>> were originally char *s.
>
> They were, and still are, expressions of type "array of char".  Such
> expressions are implicitly converted to char * in most contexts.

Indeed, the 1975 C Reference Manual (3 years before K&R1, 14 years
before the first C standard) says:

    A string is a sequence of characters surrounded by double quotes
    ``"''. A string has the type array-of-characters (see below) and
    refers to an area of storage initialized with the given characters.

(It uses the term "string" where modern C uses "string literal".)

> I point this out because your reference to what they were originally
> might lead someone to think that there has been a change in the language
> in this regard.  There hasn't been.  There was, however, what might be
> seen as a missed opportunity when const was added to the language in not
> making string laterals have type "array of const char".

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips Healthcare
void Void(void) { Void(); } /* The recursive call of the void */