3 Mar
2025
3 Mar
'25
6:27 p.m.
On Mon, Mar 03, 2025 at 05:55:10PM +0000, segaloco via TUHS wrote:
Truth be told the subjectivity of implementing struct
memory characteristics has
bewildered me more rather than less as time goes on.
Alignment is your answer. Understand that and the confusion goes away:
slovax ~/tmp cat pack.c
#include <stdio.h>
struct {
char a;
int b;
} foo;
int
main(void)
{
printf("%lu\n", sizeof(foo));
return (0);
}
slovax ~/tmp cc pack.c
slovax ~/tmp a.out
8
Even x86, it would appear, wants to do aligned loads. I'm a little
surprised by that though maybe I shouldn't be as there is a RISC
implemented by the microcode under the x86 CPU.
Does anyone know if gcc has an option to ignore alignment and pack the
structs?