Re: [ECOS] pragma pack

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Jan 09, 2008 at 03:19:28PM +0100, Alexandre wrote:
> Hi everybody (and happy new year would i add),
> 
> I'd like to use the pragma pack(1) in one of my applications to align
> properly a 5 bytes structures array into flash.
> I know that packing reduces greatly the performances of the system but
> performance is not really my problem here as i'm actually looking for
> more memory and would greatly need to pack things up a little bit.
> 
> I tried to declare the next structure as shown, with the pragmas, but
> it's still 8 bytes large, either read with a sizeof(pelco_pattern) or
> after being written in rom:
> 
> #pragma pack(1)
> typedef struct {
>    cyg_uint8 command2_byte;
>    cyg_uint8 data3;
>    cyg_uint8 data4;
>    cyg_uint16 timestamp;
> } pelco_pattern;
> #pragma pack()

Is this legal for gcc? I always use attributes. Take a look at 

http://gcc.gnu.org/onlinedocs/gcc-4.2.2/gcc/Type-Attributes.html#Type-Attributes

        Andrew

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