int evutil_make_listen_socket_reuseable(evutil_socket_t sock)；
相当于执行以下操作
int one = 1;
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &one,(ev_socklen_t)sizeof(one));
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int evutil_make_socket_nonblocking(evutil_socket_t fd);
相当于执行以下操作
int flags;
flags = fcntl(fd, F_GETFL, NULL);
flags & O_NONBLOCK;
fcntl(fd, F_SETFL, flags | O_NONBLOCK) ;
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1.event_new();间接调用event_assign();
#include <sys/time.h>
void timeradd(struct timeval *a, struct timeval *b,
struct timeval *res);
void timersub(struct timeval *a, struct timeval *b,
struct timeval *res);
void timerclear(struct timeval *tvp);
int timerisset(struct timeval *tvp);
int timercmp(struct timeval *a, struct timeval *b, CMP);