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
--
http://www.hailfinger.org/
