#define SIGEV_THREAD 2 /* deliver via thread creation */
#define SIGEV_THREAD_ID 4 /* deliver to thread */
-#define SIGEV_MAX_SIZE 64
-#ifndef SIGEV_PAD_SIZE
-#define SIGEV_PAD_SIZE ((SIGEV_MAX_SIZE/sizeof(int)) - 3)
+/*
+ * This works because the alignment is ok on all current architectures
+ * but we leave open this being overridden in the future
+ */
+#ifndef __ARCH_SIGEV_PREAMBLE_SIZE
+#define __ARCH_SIGEV_PREAMBLE_SIZE (sizeof(int) * 2 + sizeof(sigval_t))
#endif
+#define SIGEV_MAX_SIZE 64
+#define SIGEV_PAD_SIZE ((SIGEV_MAX_SIZE - __ARCH_SIGEV_PREAMBLE_SIZE) \
+ / sizeof(int))
+
typedef struct sigevent {
sigval_t sigev_value;
int sigev_signo;