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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: double strtod( const char *nPtr, char **endPrt);
Date: Thu, 12 Nov 2015 17:14:55 -0800
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supercat@casperkitty.com writes:
> On Thursday, November 12, 2015 at 2:48:23 PM UTC-6, Keith Thompson wrote:
>> A compiler doesn't create an object.  It generates code that results in
>> the creation of an object when that code is executed.
>
> I've seen a number of compilers where a file containing:
>
>     char *getmsg(int n) { return n ? "Yep" : "Nope"; }
>
> will get turned into something closer to:
>
>     static unsinged char __static_data[9] =
>       {'Y','e','p',0, 'N','o','p','e', 0};
>     char *getmsg(int n) { return n ? __static_data+0, 
>                                      __static_data+4; }
>
> So from the point of view of the linker there is for each compilation
> unit only one blob holding all the static data from that unit, rather
> than a separate blob for each string literal.  Only from the point of
> view of the compiler is "Nope\0" a distinct object.

From the point of view of the C language, the anonymous array containing
"Nope\0" is a distinct object.  Distinct objects can easily be adjacent
in memory.  But the object does not exist until after you execute the
program.

> Otherwise, my main point was that saying object is created "at
> runtime" would in most contexts imply that it was created at the point
> where the string literal was used in the code.  That is true of some
> BASIC interpreters, but is not true of typical C implementations.

But that's not what I said.  The array object has static storage
duration, so it's allocated during program startup (before main is
entered) and remains allocated until the program terminates.  That's
still run time.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"