#include <stddef.h>
#include <signal.h>

--

#define sigaltstack(member)	offsetof (stack_t, member)

sizeSS				sizeof (stack_t)
oSS_SP				sigaltstack (ss_sp)
oSS_FLAGS			sigaltstack (ss_flags)
oSS_SIZE			sigaltstack (ss_size)

SS_ONSTACK