/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
   It is considered beerware. Prost. Skol. Cheers or whatever.

   $id$ */

#ifndef OT_EVENT_H__
#define OT_EVENT_H__

#include <stdint.h>

/* Which descriptors have become readable or writable, asked of whichever
   mechanism the kernel offers. The generation a descriptor was registered
   with is handed back with every event, so a caller can tell an event for
   the connection it is holding from one for a connection that has since been
   closed and had its number reused. */

enum { EVENT_READ = 1, EVENT_WRITE = 2 };

typedef struct {
  int      fd;
  uint32_t generation;
  int      what;
} ot_event;

int  event_init(void);
void event_deinit(void);

int  event_add(int fd, int what, uint32_t generation);
int  event_modify(int fd, int what, uint32_t generation);
int  event_del(int fd);

/* Waits at most timeout_ms, or indefinitely when that is negative, and fills
   out with up to max ready descriptors. Returns how many, or -1. */
int  event_wait(ot_event *out, int max, int timeout_ms);

/* Which mechanism was compiled in, for the version string */
const char *event_mechanism(void);

#endif