usr/src/sys/sys/callout.h

/*      callout.h       4.3     81/02/27        */

/*
 * The callout structure is for
 * a routine arranging
 * to be called by the clock interrupt
 * (clock.c) with a specified argument,
 * in a specified amount of time.
 * Used, for example, to time tab
 * delays on typewriters.
 */

struct  callo
{
        int     c_time;         /* incremental time */
        caddr_t c_arg;          /* argument to routine */
        int     (*c_func)();    /* routine */
};
#ifdef KERNEL
extern  struct callo *callout;
extern  int ncallo;
#endif