Member variables in the ev_loop struct in libev

1. ev_loop is the struct used by libev to describe the event loop. The definition in libev is relatively difficult. Here we extract it and make comments to facilitate learning. Libev is defined as follows:

struct ev_loop{  ev_tstamp ev_rt_now;  #define ev_rt_now ((loop)->ev_rt_now)  #define VAR(name,decl) decl;    #include "ev_vars.h"  #undef VAR};#include "ev_wrap.h"static struct ev_loop default_loop_struct;EV_API_DECL struct ev_loop *ev_default_loop_ptr = 0;

Ev_tstamp is a double type and a time event count type. Here, define is used to define ev_rt_now as (loop)-> ev_rt_now). You can directly use ev_rt_now in the program, this is the definition of the structure behind it. This may be some programming skills of the author.

#define VAR(name,decl) decl; #define VARx(type,name) VAR(name, type name)

The two rows indicate a meaning, and the name defined by type is equal to the type name; for example, int backend; it is equivalent to defining a variable in the struct. Specific variables are defined in the ev_vars.h header file.

The ev_warp.h file serves the same purpose as # define ev_rt_now (loop)-> ev_rt_now. The code for the two files is as follows:

#define VARx(type,name) VAR(name, type name)VARx(ev_tstamp, now_floor) /* last time we refreshed rt_time */VARx(ev_tstamp, mn_now)    /* monotonic clock "now" */VARx(ev_tstamp, rtmn_diff) /* difference realtime - monotonic time *//* for reverse feeding of events */VARx(W *, rfeeds)VARx(int, rfeedmax)VARx(int, rfeedcnt)VAR (pendings, ANPENDING *pendings [NUMPRI])VAR (pendingmax, int pendingmax [NUMPRI])VAR (pendingcnt, int pendingcnt [NUMPRI])VARx(int, pendingpri) /* highest priority currently pending */VARx(ev_prepare, pending_w) /* dummy pending watcher */VARx(ev_tstamp, io_blocktime)VARx(ev_tstamp, timeout_blocktime)VARx(int, backend)VARx(int, activecnt) /* total number of active events ("refcount") */VARx(EV_ATOMIC_T, loop_done)  /* signal by ev_break */VARx(int, backend_fd)VARx(ev_tstamp, backend_mintime) /* assumed typical timer resolution */VAR (backend_modify, void (*backend_modify)(EV_P_ int fd, int oev, int nev))VAR (backend_poll  , void (*backend_poll)(EV_P_ ev_tstamp timeout))VARx(ANFD *, anfds)VARx(int, anfdmax)VAR (evpipe, int evpipe [2])VARx(ev_io, pipe_w)VARx(EV_ATOMIC_T, pipe_write_wanted)VARx(EV_ATOMIC_T, pipe_write_skipped)#if !defined(_WIN32) || EV_GENWRAPVARx(pid_t, curpid)#endifVARx(char, postfork)  /* true if we need to recreate kernel state after fork */#if EV_USE_SELECT || EV_GENWRAPVARx(void *, vec_ri)VARx(void *, vec_ro)VARx(void *, vec_wi)VARx(void *, vec_wo)#if defined(_WIN32) || EV_GENWRAPVARx(void *, vec_eo)#endifVARx(int, vec_max)#endif#if EV_USE_POLL || EV_GENWRAPVARx(struct pollfd *, polls)VARx(int, pollmax)VARx(int, pollcnt)VARx(int *, pollidxs) /* maps fds into structure indices */VARx(int, pollidxmax)#endif#if EV_USE_EPOLL || EV_GENWRAPVARx(struct epoll_event *, epoll_events)VARx(int, epoll_eventmax)VARx(int *, epoll_eperms)VARx(int, epoll_epermcnt)VARx(int, epoll_epermmax)#endif#if EV_USE_KQUEUE || EV_GENWRAPVARx(pid_t, kqueue_fd_pid)VARx(struct kevent *, kqueue_changes)VARx(int, kqueue_changemax)VARx(int, kqueue_changecnt)VARx(struct kevent *, kqueue_events)VARx(int, kqueue_eventmax)#endif#if EV_USE_PORT || EV_GENWRAPVARx(struct port_event *, port_events)VARx(int, port_eventmax)#endif#if EV_USE_IOCP || EV_GENWRAPVARx(HANDLE, iocp)#endifVARx(int *, fdchanges)VARx(int, fdchangemax)VARx(int, fdchangecnt)VARx(ANHE *, timers)VARx(int, timermax)VARx(int, timercnt)#if EV_PERIODIC_ENABLE || EV_GENWRAPVARx(ANHE *, periodics)VARx(int, periodicmax)VARx(int, periodiccnt)#endif#if EV_IDLE_ENABLE || EV_GENWRAPVAR (idles, ev_idle **idles [NUMPRI])VAR (idlemax, int idlemax [NUMPRI])VAR (idlecnt, int idlecnt [NUMPRI])#endifVARx(int, idleall) /* total number */VARx(struct ev_prepare **, prepares)VARx(int, preparemax)VARx(int, preparecnt)VARx(struct ev_check **, checks)VARx(int, checkmax)VARx(int, checkcnt)#if EV_FORK_ENABLE || EV_GENWRAPVARx(struct ev_fork **, forks)VARx(int, forkmax)VARx(int, forkcnt)#endif#if EV_CLEANUP_ENABLE || EV_GENWRAPVARx(struct ev_cleanup **, cleanups)VARx(int, cleanupmax)VARx(int, cleanupcnt)#endif#if EV_ASYNC_ENABLE || EV_GENWRAPVARx(EV_ATOMIC_T, async_pending)VARx(struct ev_async **, asyncs)VARx(int, asyncmax)VARx(int, asynccnt)#endif#if EV_USE_INOTIFY || EV_GENWRAPVARx(int, fs_fd)VARx(ev_io, fs_w)VARx(char, fs_2625) /* whether we are running in linux 2.6.25 or newer */VAR (fs_hash, ANFS fs_hash [EV_INOTIFY_HASHSIZE])#endifVARx(EV_ATOMIC_T, sig_pending)#if EV_USE_SIGNALFD || EV_GENWRAPVARx(int, sigfd)VARx(ev_io, sigfd_w)VARx(sigset_t, sigfd_set)#endifVARx(unsigned int, origflags) /* original loop flags */#if EV_FEATURE_API || EV_GENWRAPVARx(unsigned int, loop_count) /* total number of loop iterations/blocks */VARx(unsigned int, loop_depth) /* #ev_run enters - #ev_run leaves */VARx(void *, userdata)/* C++ doesn‘t support the ev_loop_callback typedef here. stinks. */VAR (release_cb, void (*release_cb)(EV_P) EV_THROW)VAR (acquire_cb, void (*acquire_cb)(EV_P) EV_THROW)VAR (invoke_cb , ev_loop_callback invoke_cb)#endif#undef VARx

 

#define acquire_cb ((loop)->acquire_cb)#define activecnt ((loop)->activecnt)#define anfdmax ((loop)->anfdmax)#define anfds ((loop)->anfds)#define async_pending ((loop)->async_pending)#define asynccnt ((loop)->asynccnt)#define asyncmax ((loop)->asyncmax)#define asyncs ((loop)->asyncs)#define backend ((loop)->backend)#define backend_fd ((loop)->backend_fd)#define backend_mintime ((loop)->backend_mintime)#define backend_modify ((loop)->backend_modify)#define backend_poll ((loop)->backend_poll)#define checkcnt ((loop)->checkcnt)#define checkmax ((loop)->checkmax)#define checks ((loop)->checks)#define cleanupcnt ((loop)->cleanupcnt)#define cleanupmax ((loop)->cleanupmax)#define cleanups ((loop)->cleanups)#define curpid ((loop)->curpid)#define epoll_epermcnt ((loop)->epoll_epermcnt)#define epoll_epermmax ((loop)->epoll_epermmax)#define epoll_eperms ((loop)->epoll_eperms)#define epoll_eventmax ((loop)->epoll_eventmax)#define epoll_events ((loop)->epoll_events)#define evpipe ((loop)->evpipe)#define fdchangecnt ((loop)->fdchangecnt)#define fdchangemax ((loop)->fdchangemax)#define fdchanges ((loop)->fdchanges)#define forkcnt ((loop)->forkcnt)#define forkmax ((loop)->forkmax)#define forks ((loop)->forks)#define fs_2625 ((loop)->fs_2625)#define fs_fd ((loop)->fs_fd)#define fs_hash ((loop)->fs_hash)#define fs_w ((loop)->fs_w)#define idleall ((loop)->idleall)#define idlecnt ((loop)->idlecnt)#define idlemax ((loop)->idlemax)#define idles ((loop)->idles)#define invoke_cb ((loop)->invoke_cb)#define io_blocktime ((loop)->io_blocktime)#define iocp ((loop)->iocp)#define kqueue_changecnt ((loop)->kqueue_changecnt)#define kqueue_changemax ((loop)->kqueue_changemax)#define kqueue_changes ((loop)->kqueue_changes)#define kqueue_eventmax ((loop)->kqueue_eventmax)#define kqueue_events ((loop)->kqueue_events)#define kqueue_fd_pid ((loop)->kqueue_fd_pid)#define loop_count ((loop)->loop_count)#define loop_depth ((loop)->loop_depth)#define loop_done ((loop)->loop_done)#define mn_now ((loop)->mn_now)#define now_floor ((loop)->now_floor)#define origflags ((loop)->origflags)#define pending_w ((loop)->pending_w)#define pendingcnt ((loop)->pendingcnt)#define pendingmax ((loop)->pendingmax)#define pendingpri ((loop)->pendingpri)#define pendings ((loop)->pendings)#define periodiccnt ((loop)->periodiccnt)#define periodicmax ((loop)->periodicmax)#define periodics ((loop)->periodics)#define pipe_w ((loop)->pipe_w)#define pipe_write_skipped ((loop)->pipe_write_skipped)#define pipe_write_wanted ((loop)->pipe_write_wanted)#define pollcnt ((loop)->pollcnt)#define pollidxmax ((loop)->pollidxmax)#define pollidxs ((loop)->pollidxs)#define pollmax ((loop)->pollmax)#define polls ((loop)->polls)#define port_eventmax ((loop)->port_eventmax)#define port_events ((loop)->port_events)#define postfork ((loop)->postfork)#define preparecnt ((loop)->preparecnt)#define preparemax ((loop)->preparemax)#define prepares ((loop)->prepares)#define release_cb ((loop)->release_cb)#define rfeedcnt ((loop)->rfeedcnt)#define rfeedmax ((loop)->rfeedmax)#define rfeeds ((loop)->rfeeds)#define rtmn_diff ((loop)->rtmn_diff)#define sig_pending ((loop)->sig_pending)#define sigfd ((loop)->sigfd)#define sigfd_set ((loop)->sigfd_set)#define sigfd_w ((loop)->sigfd_w)#define timeout_blocktime ((loop)->timeout_blocktime)#define timercnt ((loop)->timercnt)#define timermax ((loop)->timermax)#define timers ((loop)->timers)#define userdata ((loop)->userdata)#define vec_eo ((loop)->vec_eo)#define vec_max ((loop)->vec_max)#define vec_ri ((loop)->vec_ri)#define vec_ro ((loop)->vec_ro)#define vec_wi ((loop)->vec_wi)#define vec_wo ((loop)->vec_wo)

Member variables in the ev_loop struct in libev