Mailinglist Archive: opensuse-programming (58 mails)

[Mark Gray <markgray-temp-1072781312@xxxxxxxxxxxx>]

Marcus Meissner <meissner@xxxxxxx> writes:
>> But why is there no warning when optimization is turned on?  (When the
>> warning is actually needed :-)  This is my main point.
> 
> It is there with -Wall on SuSE Linux 9.0:
> 
> $ cat xx.c 
> void f(char *s) {
>         while (*s) {
> 		*s++ = *s | 0x20;
> 	}
> }
> $ gcc -O2 -Wall -c xx.c 
> xx.c: In function `f':
> xx.c:3: Warnung: operation on `s' may be undefined

It is the toupper that turns it off then:

markgray@soyo:/usr/src/packages/BUILD/bug> cat xx.c
#include <ctype.h>

void strupr_OLD (char *s)
{
    while (*s) {
        *s++ = toupper(*s);
    }
}

markgray@soyo:/usr/src/packages/BUILD/bug> gcc -O2 -Wall -c xx.c
markgray@soyo:/usr/src/packages/BUILD/bug>

(This is also 9.0 btw)