Re: [AD] fixed gcc warning

[Elias Pschernig <elias@xxxxxxxxxx>]

On Sun, 2004-07-18 at 21:01 +0200, Eric Botcazou wrote:
> > The attached patch makes Allegro's C-only version compile with --enable-
> > strict-warn and gcc 3.3.4. Without it, I get this:
> >
> > src/c/cstretch.c: In function `stretch_line15':
> > src/c/cstretch.c:104: warning: use of cast expressions as lvalues is
> > deprecated
> >
> > And some more of that.
> 
> My bad, I forgot to check the C-only version.
> 
> > After someone confirms there's no problem with it (there'd be no more
> > need at all for the type parameter now, and I'm not too sure what the
> > cast around an lavalue actually does - so I might be overlooking
> > something), I'll commit it.
> 
> Without the extension (i.e. by following ISO C), the expression
> 
> (unsigned char*) s
> 
> is not a lvalue (ISO C99 6.5.4 §4 note 85 :-) so it can't be the destination 
> of an assignment.
> 
> 
> I think this part of the patch is wrong:
> 
> -type *s = (type*) sptr;                                                   \
> +unsigned char *s = sptr;                                                   \
> 
> because of
> 
>     set(d, get(s));                                                        \
> 
> where the 'get' can be the dereference operator '*', as in
> 
> static void stretch_line15(unsigned long dptr, unsigned char *sptr)
> {
>    DECLARE_STRETCHER(unsigned short, sizeof(unsigned short), bmp_write15, *);
> }
> 

Oops, yes, and i only tested with 8-bit :| I thought get is a function
call. I'll commit the attached patch instead (and this time actually
taking the time to check all calls of the macros).

-- 
Elias Pschernig

Index: src/c/cstretch.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/c/cstretch.c,v
retrieving revision 1.10
diff -u -p -r1.10 cstretch.c
--- src/c/cstretch.c	26 Mar 2003 10:27:28 -0000	1.10
+++ src/c/cstretch.c	18 Jul 2004 22:51:50 -0000
@@ -39,10 +39,10 @@ unsigned long d = dptr;                 
 unsigned long dend = d + _al_stretch.dw;                                  \
 ASSERT(s);                                                                \
 ASSERT(d);                                                                \
-for (; d < dend; d += (size), (unsigned char*) s += _al_stretch.sinc) {   \
+for (; d < dend; d += (size), s = (unsigned char*)s + _al_stretch.sinc) { \
    set(d, get(s));                                                        \
    if (dd >= 0)                                                           \
-      (unsigned char*) s += (size), dd += _al_stretch.i2;                 \
+      s = (unsigned char*)s + (size), dd += _al_stretch.i2;               \
    else                                                                   \
       dd += _al_stretch.i1;                                               \
 }
@@ -137,12 +137,12 @@ unsigned long d = dptr;                 
 unsigned long dend = d + _al_stretch.dw;                                  \
 ASSERT(s);                                                                \
 ASSERT(d);                                                                \
-for (; d < dend; d += (size), (unsigned char*) s += _al_stretch.sinc) {   \
+for (; d < dend; d += (size), s = (unsigned char*)s + _al_stretch.sinc) { \
    unsigned long color = get(s);                                          \
    if (color != (mask))                                                   \
    set(d, color);                                                         \
    if (dd >= 0)                                                           \
-      (unsigned char*) s += (size), dd += _al_stretch.i2;                 \
+      s = (unsigned char*)s + (size), dd += _al_stretch.i2;               \
    else                                                                   \
       dd += _al_stretch.i1;                                               \
 }