From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Sun,  7 Nov 2010 13:32:09 +0100
From: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
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To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
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Subject: Re: [9fans] pcc limitation?
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On 07.11.2010 05:02, Federico G. Benavento wrote:
> the syntax (){} is for structures, like (Point){0, 0} or something,
> so you don't need the braces there, just the cast
>
>                .writearr       = (const unsigned char*)JEDEC_WREN,
>

writearr should point to a one-member const unsigned char array, and the
zeroth element of that array has the value JEDEC_WREN.

Your suggested code has different behaviour (it casts a uchar to uchar *):

#include <stddef.h>
#include <stdio.h>
#define JEDEC_WREN              0x06
struct spi_command {
        const unsigned char *writearr;
};
int main(int argc, char *argv[])
{
        struct spi_command cmds[] = {
        {
                .writearr       = (const unsigned char[]){ JEDEC_WREN },
        },{
                .writearr       = (const unsigned char *)JEDEC_WREN,
        }};
        printf("Mine: writearr=%p\n", cmds[0].writearr);
        printf("Mine: writearr[0]=0x%02hhx\n", cmds[0].writearr[0]);
        printf("Federico: writearr=%p\n", cmds[1].writearr);
        printf("Federico: writearr[0]=0x%02hhx\n", cmds[1].writearr[0]);
        return 0;
}

Output is:
Mine: writearr=0xbf8eb213
Mine: writearr[0]=0x06
Federico: writearr=0x6
Segmentation fault

Regards,
Carl-Daniel

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