如果将key定义为std :: string，则redis中存储的pod结构的反序列化将失败

Question

在redis中存储POD结构与DECLARE @id TABLE (id int, childId int); INSERT INTO @id SELECT 1, 2; INSERT INTO @id SELECT 2, 4; INSERT INTO @id SELECT 3, 5; INSERT INTO @id SELECT 4, 6; INSERT INTO @id SELECT 5, null; INSERT INTO @id SELECT 6, null; WITH cte AS ( SELECT id, childId, id AS anchorId FROM @id WHERE id IN (1,3) UNION ALL SELECT b.id, b.childId, cte.anchorId FROM @id b INNER JOIN cte ON b.id = cte.childId ) SELECT id , childId , CASE WHEN id = anchorId THEN NULL ELSE anchorId END AS anchorId FROM cte 一起正常工作，但如果涉及const char *则不行。

const char * example

std::string

如果我换行：

#include <hiredis/hiredis.h>
#include <string.h>
#include <string>
#include <iostream>

using namespace std;

struct Test
{
  const uint32_t id;
  const char *name;
};
int main() {
  redisContext *context = redisConnect("127.0.0.1", 6379);
  if (context == NULL || context->err) {
      if (context) {
          printf("Error: %s\n", context->errstr);
      } else {
          printf("Can't allocate redis context\n");
      }
      exit(EXIT_FAILURE);
  }

  Test obj = {(uint32_t) 123, "foo bar"};

  const size_t size = 2 * sizeof(uint32_t) + (strlen(obj.name) + 1);

  cout << "object{id: " << obj.id << ", name:' " << obj.name << "'}; size: " << size << endl;

  redisReply *reply = 0;

  const char *key = strdup("some-key");
  reply = (redisReply *) redisCommand(context, "SET %b %b", key, strlen(key), &obj, size);

  if (!reply)
      return REDIS_ERR;

  freeReplyObject(reply);

  reply = (redisReply *) redisCommand(context, "GET %s", key);
  if (!reply)
      return REDIS_ERR;

  Test *res = (struct Test*) reply->str;
  cout << "result{id: " << res->id << ", name:' " << res->name << "'}; size: " << size << endl;

  freeReplyObject(reply);
  redisFree(context);
}

与

  const char *key = strdup("some-key");
  reply = (redisReply *) redisCommand(context, "SET %b %b", key, strlen(key), &obj, size);

执行始终以分段错误结束。

我不能自己解决这个问题，我真的很感激任何帮助。

Answer 1

好的，我明白了： 替换第二个redisCommand语句

reply = (redisReply *) redisCommand(context, "GET %b", key.c_str(), key.size());

解决了这个问题。