CALLOUT_INIT
#define CALLOUT_INIT(c) callout_init((c), 0)
#define CALLOUT_INIT(c) callout_init((c))
#define CALLOUT_INIT(c) do { (void)memset((c), 0, sizeof(*(c))); } while (/*CONSTCOND*/ 0)
#define CALLOUT_INIT(c) do { (void)memset((c), 0, sizeof(*(c))); } while (/*CONSTCOND*/ 0)