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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: No warning at implicit removal of const. Was: relearning C: why does an in-place change to a char* segfault?
Date: Fri, 02 Aug 2024 03:02:03 -0700
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candycanearter07 <candycanearter07@candycanearter07.nomail.afraid>
writes:
> David Brown <david.brown@hesbynett.no> wrote at 17:56 this Thursday (GMT):
[...]
>> gcc has the option "-Wwrite-strings" that makes string literals in C 
>> have "const char" array type, and thus give errors when you try to 
>> assign to a non-const char * pointer.  But the option has to be 
>> specified explicitly (it is not in -Wall) because it changes the meaning 
>> of the code and can cause compatibility issues with existing correct code.
>
> -Wwrite-strings is included in -Wpedantic.

No it isn't, nor is it included in -Wall -- and it wouldn't make sense
to do so.

The -Wpedantic option is intended to produce all required diagnostics
for the specified C standard.  -Wwrite-strings gives string literals the
type `const char[LENGTH]`, which enables useful diagnostics but is
*non-conforming*.

For example, this program:

```
#include <stdio.h>
int main(void) {
    char *s = "hello, world";
    puts(s);
}
```

is valid (no diagnostic required), since it doesn't actually write to
the string literal object, but `-Wwrite-strings` causes gcc to warn
about it (because making the pointer non-const creates the potential for
an error).

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */