Re: [PATCH] Use unsigned char to squash compiler warnings

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 4, 2015, 22:11 UTC
Message-ID: <xmqqd24o76rh.fsf@gitster.dls.corp.google.com>
In-Reply-To: <CAP30j1684A=QsA0o+zLMP70V09mFTS_MtiPZB2TrRywYK2NWWw@mail.gmail.com>

Ben Walton <bdwalton@gmail.com> writes:

Show 7 quoted lines

> On Mon, Mar 2, 2015 at 8:30 PM Junio C Hamano <gitster@pobox.com> wrote:
>
>> The conversion looked good from a cursory view; I didn't check it
>> very carefully though.
>>
> Yes, because of the Solaris ABI, the Studio compiler defaults char to
> signed char.

Doesn't our beloved GCC also uses signed char when you write char? You keep saying that "defaults to signed char is the problem", but that does not explain why those in the rest of the world outside the Solaris land do not encounter this problem.

	$ cat >x.c <<\EOF
        #include <stdio.h>
        int main (void) {
                SIGNED char ch = 0xff;
                printf("%d\n", ch);
                return 0;
        }
	EOF
        $ gcc -Wall -DSIGNED= x.c && ./a.out
        -1
        $ gcc -Wall -DSIGNED=signed x.c && ./a.out
	-1

I think th problem is not Solaris uses signed char for char like everybody else does ;-) but it gives a fairly useless warning to annoy people.

In any case, here is what I queued, FYI, on bw/kwset-use-unsigned topic.

Thanks.

commit 189c860c9ec5deb95845c056ca5c15b58970158e
Author: Ben Walton <bdwalton@gmail.com>
Date:   Mon Mar 2 19:22:31 2015 +0000

    kwset: use unsigned char to store values with high-bit set
    
    Sun Studio on Solaris issues warnings about improper initialization
    values being used when defining tolower_trans_tbl[] in ctype.c.  The
    array wants to store values with high-bit set and treat them as
    values between 128 to 255.  Unlike the rest of the Git codebase
    where we explicitly specify 'unsigned char' for such variables and
    arrays, however, kwset code we borrowed from elsewhere uses 'char'
    for this and other variables.
    
    Fix the declarations to explicitly use 'unsigned char' where
    necessary to bring it in line with the rest of the Git.
    
    Signed-off-by: Ben Walton <bdwalton@gmail.com>
    Signed-off-by: Junio C Hamano <gitster@pobox.com>