CodeWarrior for MCU中的主题 CW10.2 Structure Packing issues

CW10.2 Structure Packing issues

ignisuti — Thu, 29 Oct 2020 09:02:26 GMT

Can someone please help me explain why sizeof( EVENT_LOG_t ) returns 8? It should be 6, right?

Does this have something to do with the way this structure is packed? How can I fix this?

My target MCU is Kinetis K10.

typedef struct  {  u32 time;  u8 type;  u8 code;}EVENT_LOG_t;

stanish — Fri, 27 Apr 2012 16:01:43 GMT

Hello ignisuti,

You are right. This is caused by adding the padding bytes to keep data alignment.

If you need to get rid of these padding bytes you can add pragma:

#pragma pack(1)

but this might have an impact on speed performance.

Stanish