topic Re: aligned attribute issue in CodeWarrior for MCU

aligned attribute issue

cencongsu — Wed, 20 Apr 2016 03:00:27 GMT

From the MCU Kinetis Builds Reference Manual, I see:

I have a code like:

struct ss

{

char a;

int b __attribute__ ((aligned(1)));

};

I compile it with codewarrior 10.6 and use sizeof() to check the size of this struct, And I found the size is 8, and then I check the address of a and b, found their address still align at 4.

But I mean to make b align at 1, so the size of the struct shall be 5.

Did I misunderstand something or I miss something?

Re: aligned attribute issue

Alice_Yang — Tue, 26 Apr 2016 02:54:50 GMT

Hello cencong,

In the structure ss ,the longest is the "int b" it is 4 byte ,

so in the (aligned(x)), the x minimum should be 4 , 1 is wrong.

If you write 1, it is default use the 4 to calculate .

Hope it hleps

Have a great day,
Alice

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Re: aligned attribute issue

cencongsu — Wed, 27 Apr 2016 01:43:21 GMT

So I guess the document description is wrong.