Subject: Re: bug#40671: [DOC] modify literal objects

From: Paul Eggert <[email-masked]>
Date: Sat, 25 Apr 2020 20:49:27 -0700

On 4/25/20 12:30 PM, Dmitry Gutov wrote:
> On 25.04.2020 06:20, Paul Eggert wrote:
>>> When a value is constant in C or C++, you can't change it.
>> Yes, you can't change it in a portable program, because if you attempt to change
>> it the resulting behavior is undefined. The attempt might succeed so that the
>> "constant" is changed, or you might get a core dump, or you might get an
>> exception, or something else might happen.
> 
> Might succeed? Will it even compile?

Yes, although the C/C++ program must type-check and satisfy all other static
constraints of course (otherwise it won't compile). Here's a simple example:

#include <string.h>
int main (void) { return !strcpy ("a", "b"); }

This function attempts to modify the "a" string constant, so it might dump core,
or might return 0, or might do other things.