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Is a char array initializer a "string literal"?

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  Is a char array initializer a "string literal"? Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 07:57 +0000
    Re: Is a char array initializer a "string literal"? Muttley@dastardlyhq.com - 2022-07-26 08:03 +0000
    Re: Is a char array initializer a "string literal"? Öö Tiib <ootiib@hot.ee> - 2022-07-26 01:51 -0700
      Re: Is a char array initializer a "string literal"? Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 10:07 +0000
        Re: Is a char array initializer a "string literal"? Öö Tiib <ootiib@hot.ee> - 2022-07-26 05:10 -0700
          Re: Is a char array initializer a "string literal"? Öö Tiib <ootiib@hot.ee> - 2022-07-26 06:18 -0700
          Re: Is a char array initializer a "string literal"? Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 16:03 +0000
            Re: Is a char array initializer a "string literal"? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-07-26 18:18 +0200
              Re: Is a char array initializer a "string literal"? Juha Nieminen <nospam@thanks.invalid> - 2022-07-27 07:40 +0000
                Re: Is a char array initializer a "string literal"? Öö Tiib <ootiib@hot.ee> - 2022-07-27 01:17 -0700
    Re: Is a char array initializer a "string literal"? Bo Persson <bo@bo-persson.se> - 2022-07-26 11:11 +0200
    Re: Is a char array initializer a "string literal"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-07-26 02:30 -0700
      Re: Is a char array initializer a "string literal"? Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 10:19 +0000
      Re: Is a char array initializer a "string literal"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-26 12:03 -0700
        Re: Is a char array initializer a "string literal"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-07-27 01:56 -0700
          Re: Is a char array initializer a "string literal"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-27 11:02 -0700
    Re: Is a char array initializer a "string literal"? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-07-26 11:36 +0200
      Re: Is a char array initializer a "string literal"? Juha Nieminen <nospam@thanks.invalid> - 2022-07-26 10:22 +0000
        Re: Is a char array initializer a "string literal"? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2022-07-26 16:50 +0200
    Re: Is a char array initializer a "string literal"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-26 12:13 -0700
    Re: Is a char array initializer a "string literal"? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-07-26 17:56 -0700
      Re: Is a char array initializer a "string literal"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-26 19:24 -0700
        Re: Is a char array initializer a "string literal"? Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-07-27 13:05 -0700
          Re: Is a char array initializer a "string literal"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-07-27 15:38 -0700

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#85672

On 7/26/2022 12:57 AM, Juha Nieminen wrote:
> In another forum I was discussing string literals and char arrays.
> During the conversation this question occurred to me:
> In an array initialization like this:
> 
>      char str[] = "hello";
> 
> can that "hello" even be considered a "string literal", or should it
> be classified as something else?

Yes, it is a string literal. I.e. formally it is an independent object 
with static storage duration, independent and separate from `str` in 
your example.

> The question arose because an (actual) string literal has a type of
> array-of-const-char (of a size needed to store the contents of the
> string literal). So for example the type of "hello" is const char[6].
> 
> However, you can't initialize an array with another array. 

But you _can_ initialize a char array with a string literal. A special 
exception is deliberately made for this specific case in C and C++ 
standards. They explicitly state that you _can_ initialize a char array 
with a string literal and explicitly specify the semantics of such 
initialization.

-- 
Best regards,
Andrey

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#85673

Andrey Tarasevich <andreytarasevich@hotmail.com> writes:
> On 7/26/2022 12:57 AM, Juha Nieminen wrote:
>> In another forum I was discussing string literals and char arrays.
>> During the conversation this question occurred to me:
>> In an array initialization like this:
>>      char str[] = "hello";
>> can that "hello" even be considered a "string literal", or should it
>> be classified as something else?
>
> Yes, it is a string literal. I.e. formally it is an independent object
> with static storage duration, independent and separate from `str` in 
> your example.

It is a string literal, i.e., it is a source code token starting and
ending with a '"' character.  The corresponding object with static
storage duration is not a string literal.  It doesn't exist until
execution time.

[...]

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

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#85704

On 7/26/2022 7:24 PM, Keith Thompson wrote:
> Andrey Tarasevich <andreytarasevich@hotmail.com> writes:
>> On 7/26/2022 12:57 AM, Juha Nieminen wrote:
>>> In another forum I was discussing string literals and char arrays.
>>> During the conversation this question occurred to me:
>>> In an array initialization like this:
>>>       char str[] = "hello";
>>> can that "hello" even be considered a "string literal", or should it
>>> be classified as something else?
>>
>> Yes, it is a string literal. I.e. formally it is an independent object
>> with static storage duration, independent and separate from `str` in
>> your example.
> 
> It is a string literal, i.e., it is a source code token starting and
> ending with a '"' character.  The corresponding object with static
> storage duration is not a string literal.  It doesn't exist until
> execution time.

No. The distinctions is there, but it is different.

While it is true that the standard text differentiates between 
lexical/grammatical `string-literal` (hyphenated) and "string literal 
object", the former is generally treated as an expression, not as a mere 
token in source code. For example, in 7.5.1: "[...] A string-literal is 
an lvalue. [...]".

A "string literal" is an expression that evaluates to a "string literal 
object".

Also, Note 7 on 5.13.5 (admittedly non-normative) goes as far as stating 
"The effect of attempting to modify a string-literal is undefined." I 
hope you understand that this not not an attempt to dissuade us from 
modifying the source code of our programs.

These nothing wrong with taking the same terminological liberties in a 
Usenet discussion.

-- 
Best regards,
Andrey

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#85706

Andrey Tarasevich <andreytarasevich@hotmail.com> writes:
> On 7/26/2022 7:24 PM, Keith Thompson wrote:
>> Andrey Tarasevich <andreytarasevich@hotmail.com> writes:
>>> On 7/26/2022 12:57 AM, Juha Nieminen wrote:
>>>> In another forum I was discussing string literals and char arrays.
>>>> During the conversation this question occurred to me:
>>>> In an array initialization like this:
>>>>       char str[] = "hello";
>>>> can that "hello" even be considered a "string literal", or should it
>>>> be classified as something else?
>>>
>>> Yes, it is a string literal. I.e. formally it is an independent object
>>> with static storage duration, independent and separate from `str` in
>>> your example.
>> It is a string literal, i.e., it is a source code token starting and
>> ending with a '"' character.  The corresponding object with static
>> storage duration is not a string literal.  It doesn't exist until
>> execution time.
>
> No. The distinctions is there, but it is different.

I don't think it's different.

> While it is true that the standard text differentiates between
> lexical/grammatical `string-literal` (hyphenated) and "string literal 
> object", the former is generally treated as an expression, not as a
> mere token in source code. For example, in 7.5.1: "[...] A
> string-literal is an lvalue. [...]".

It's a token and it's an expression.  "A *literal* is a primary
expression" [expr.prim.literal].

> A "string literal" is an expression that evaluates to a "string
> literal object".

Yes.  How does that disagree with what I wrote?  (A string literal
object is not a string literal.)

> Also, Note 7 on 5.13.5 (admittedly non-normative) goes as far as
> stating "The effect of attempting to modify a string-literal is
> undefined." I hope you understand that this not not an attempt to
> dissuade us from modifying the source code of our programs.

Yes.  It would have been more precise to say that "The effect of
attempting to modify a string literal object is undefined."  The current
wording is informal, and I don't have a huge problem with it.

> These nothing wrong with taking the same terminological liberties in a
> Usenet discussion.

Unless the point of confusion in the original post is precisely the
distinction I pointed out.

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

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