redisContext* redisConnect(const char *ip, int port);

void *redisCommand(redisContext *c, const char *format...);

void freeReplyObject(void *reply);

void redisFree(redisContext *c)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<hiredis/hiredis.h>

int main(int argc, char **argv) {
 unsigned int j, isunix = 0;
 redisContext *c;		
 redisReply *reply;		：
 const char *hostname = (argc > 1) "127.0.0.1";

 if (argc > 2) {
  if (*argv[2] == 'u' || *argv[2] == 'U') {
   isunix = 1;
   /* in this case, host is the path to the unix socket */
   printf("Will connect to unix socket @%s\n", hostname);
  }
 }

 int port = (argc > 2) "Connection error: %s\n", c->errstr);	
   redisFree(c);	//释放redisConnect()所产生的连接。
  } else {
   printf("Connection error: can't allocate redis context\n");
  }
  exit(1);
 }

	 /* PING server */
 reply = redisCommand(c,"PING");	
 //该函数用于执行redis数据库中的命令，第一个参数为连接数据库返回的redisContext，剩下的参数为变参.。
	//此函数的返回值为void*，但是一般会强制转换为redisReply类型，以便做进一步的处理。
 
 printf("PING: %s\n", reply->str);
 freeReplyObject(reply);	//释放redisCommand执行后返回的的redisReply所占用的内存。

	 /* Set a key */
 reply = redisCommand(c,"SET %s %s", "foo", "hello world");
 printf("SET: %s\n", reply->str);
 freeReplyObject(reply);

 /* Set a key using binary safe API */
 reply = redisCommand(c,"SET %b %b", "bar", (size_t) 3, "hello", (size_t) 5);
 printf("SET (binary API): %s\n", reply->str);
 freeReplyObject(reply);

 /* Try a GET and two INCR */
 reply = redisCommand(c,"GET foo");
 printf("GET foo: %s\n", reply->str);
 freeReplyObject(reply);

 reply = redisCommand(c,"INCR counter");
 printf("INCR counter: %lld\n", reply->integer);
 freeReplyObject(reply);
 /* again ... */
 reply = redisCommand(c,"INCR counter");
 printf("INCR counter: %lld\n", reply->integer);
 freeReplyObject(reply);

 /* Create a list of numbers, from 0 to 9 */
 reply = redisCommand(c,"DEL mylist");
 freeReplyObject(reply);
 for (j = 0; j < 10; j++) {
  char buf[64];
  snprintf(buf,64,"%u",j);
  reply = redisCommand(c,"LPUSH mylist element-%s", buf);
  freeReplyObject(reply);
 }

 /* Let's check what we have inside the list */
 reply = redisCommand(c,"LRANGE mylist 0 -1");
 if (reply->type == REDIS_REPLY_ARRAY) {
  for (j = 0; j < reply->elements; j++) {
   printf("%u) %s\n", j, reply->element[j]->str);
  }
 }
 freeReplyObject(reply);

 /* Disconnects and frees the context */
 redisFree(c);

 return 0;
}