On Wed, Jun 20, 2012 at 09:09:53PM +0200, Juergen Beisert wrote:
> Hi Uwe,
>
> Uwe Kleine-König wrote:
> > On Wed, Jun 20, 2012 at 05:08:52PM +0200, Juergen Beisert wrote:
> > > Marc Kleine-Budde wrote:
> > > > [...]
> > > >
> > > > > +
> > > > > +#include <common.h>
> > > > > +#include <init.h>
> > > > > +#include <environment.h>
> > > > > +#include <globalvar.h>
> > > > > +#include <reset_source.h>
> > > > > +
> > > > > +static const char name[] = "global.system.reset";
> > > > > +static const char unknown_reset[] = "unknown";
> > > > > +static const char power_on_reset[] = "POR";
> > > > > +static const char manual_reset[] = "RST";
> > > > > +static const char watchdog[] = "WDG";
> > > > > +static const char wake[] = "WKE";
> > > > > +static const char jtag[] = "JTAG";
> > > >
> > > > what about using an array
> > > >
> > > > static cost char *reset_reason_array[] = {
> > > > [RESET_UKWN] = "unknown",
> > > > ...
> > > > };
> > >
> > > The result is not the same. The strings are no longer "const". But it
> > > should
> >
> > <kidding>Of course they are not "const" if you write "cost".</kidding>
> > Using
> >
> > static const char * const reset_reason_array[] = {
> >
> > should do the trick.
>
> No, it doesn't. Only this would:
>
> static const bla[] = "this is a really constant string";
> static const char * const reset_reason_array[] = {
> [0] = bla,
> [...]
> };
What makes you think it's not const. I think it is, look:
ukleinek@perseus:~/tmp$ cat test.c
static const char * const const_reset_reason_array[] = {
"jtag",
"por",
};
static const char *reset_reason_array[] = {
"jtag",
"por",
};
void somefunc(void)
{
char *reason = const_reset_reason_array[0];
}
ukleinek@perseus:~/tmp$ gcc -Wall -c test.c
test.c: In function ‘somefunc’:
test.c:13:17: warning: initialization discards ‘const’ qualifier from pointer target type [enabled by default]
test.c:13:8: warning: unused variable ‘reason’ [-Wunused-variable]
test.c: At top level:
test.c:6:20: warning: ‘reset_reason_array’ defined but not used [-Wunused-variable]
ukleinek@perseus:~/tmp$ objdump -D -j .rodata -j .data test.o
test.o: file format elf64-x86-64
Disassembly of section .data:
0000000000000000 <reset_reason_array>:
...
Disassembly of section .rodata:
0000000000000000 <const_reset_reason_array-0x10>:
0: 6a 74 pushq $0x74
2: 61 (bad)
3: 67 00 70 6f add %dh,0x6f(%eax)
7: 72 00 jb 9 <const_reset_reason_array-0x7>
9: 00 00 add %al,(%rax)
b: 00 00 add %al,(%rax)
d: 00 00 add %al,(%rax)
...
0000000000000010 <const_reset_reason_array>:
...
so const_reset_reason_array lives in .rodata and assinging
const_reset_reason_array[0] to a char * results in a warning.
What am I missing?
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
_______________________________________________
barebox mailing list
barebox@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/barebox
