什么是 IO 模型

#include
#include 
#include string.h>
#include 
#include 
#include 
#define TRUE 1static const char* state2String(int state)
{
if (state == 0)return "CLOSED_STATE";
if (state == ZOO_CONNECTING_STATE)return "CONNECTING_STATE";
if (state == ZOO_ASSOCIATING_STATE)return "ASSOCIATING_STATE";
if (state == ZOO_CONNECTED_STATE)return "CONNECTED_STATE";
if (state == ZOO_EXPIRED_SESSION_STATE)return "EXPIRED_SESSION_STATE";
if (state == ZOO_AUTH_FAILED_STATE)return "AUTH_FAILED_STATE";
return "INVALID_STATE";

}
static const char* type2String(int state)
{if (state == ZOO_CREATED_EVENT)return "CREATED_EVENT";
if (state == ZOO_DELETED_EVENT)return "DELETED_EVENT";
if (state == ZOO_CHANGED_EVENT)return "CHANGED_EVENT";
if (state == ZOO_CHILD_EVENT)return "CHILD_EVENT";
if (state == ZOO_SESSION_EVENT)return "SESSION_EVENT";
if (state == ZOO_NOTWATCHING_EVENT)return "NOTWATCHING_EVENT";return "UNKNOWN_EVENT_TYPE";
}
void zktest_dump_stat(const struct Stat *stat) 
{char tctimes[40];char tmtimes[40];
    time_t tctime;
    time_t tmtime;if (!stat) 
    {
        fprintf(stderr,"null\n");
        return;
    }
    tctime = stat->ctime/1000;
    tmtime = stat->mtime/1000;

    ctime_r(&tmtime, tmtimes);
    ctime_r(&tctime, tctimes);

    fprintf(stderr, "\tctime = %s\tczxid=%llx\n""\tmtime=%s\tmzxid=%llx\n""\tversion=%x\taversion=%x\n""\tephemeralOwner = %llx\n",
            tctimes, stat->czxid,
            tmtimes, stat->mzxid,
            (unsigned int)stat->version, (unsigned int)stat->aversion,
            stat->ephemeralOwner);
}
void zktest_data_completion(int rc, const char *value, int value_len, const struct Stat *stat, const void *data)
 {
    fprintf(stderr, "in data completion [%s]: rc = %d\n", value, rc);
    zktest_dump_stat(stat);
}
/*process a list of string and stat*/void zktest_strings_stat_completion(int rc, const struct String_vector *strings, const struct Stat *stat, const void *data)
 {int i=0;
    fprintf(stderr, "in strings state completion [%s]: rc = %d, string count %d\n", (char *)data, rc, strings ->count);for (i=0; icount; i++) {
        printf("%d: %s\n", i, strings->data[i]);
    }
deallocate_String_vector(strings);
    zktest_dump_stat(stat);
}void zktest_string_completion(int rc, const char *name, const void *data)
 {
    fprintf(stderr, "in string completion [%s]: rc = %d\n", (char*)(data==0?"null":data), rc);
    if (!rc)
     {
        fprintf(stderr, "\tname = %s\n", name);
    }
}void zktest_stat_completion(int rc, const struct Stat *stat, const void *data)
 {if (rc == ZNONODE)
    {
        printf("node not exists\n");
    }
    fprintf(stderr, "in state completion rc = %d data=%s stat:\n", rc, (char *)data);
    zktest_dump_stat(stat);

}