c 语言线程池 连接mysql数据库 十个出现三个连接不上

最近用c语言连接mysql数据库，同事在自己电脑上编写了线程池出现十个线程有三个连接不上mysql，但在我的电脑上是没问题的。不管连接哪个数据库，
报错如下：
starting thread 0x474cc700
thread 0x474cc700 is starting to work
threadid is 0x474cc700,working on task 0
starting thread 0x47ccd700
thread 0x47ccd700 is starting to work
threadid is 0x47ccd700,working on task 1
connect failed
2003:Can't connect to MySQL server on '192.168.1.230' (111)
insert failed
starting thread 0x484ce700
thread 0x484ce700 is starting to work
threadid is 0x484ce700,working on task 2
connect failed
2003:Can't connect to MySQL server on '192.168.1.230' (111)
insert failed
starting thread 0x48ccf700
thread 0x48ccf700 is starting to work
threadid is 0x48ccf700,working on task 3
connect failed
2003:Can't connect to MySQL server on '192.168.1.230' (111)
insert failed
thread 0x47ccd700 is starting to work
threadid is 0x47ccd700,working on task 4
thread 0x484ce700 is starting to work
threadid is 0x484ce700,working on task 5
thread 0x48ccf700 is starting to work
threadid is 0x48ccf700,working on task 6
thread 0x474cc700 is starting to work
threadid is 0x474cc700,working on task 7
thread 0x47ccd700 is starting to work
threadid is 0x47ccd700,working on task 8
thread 0x48ccf700 is starting to work
threadid is 0x48ccf700,working on task 9
thread 0x484ce700 is waiting
thread 0x474cc700 is waiting
thread 0x47ccd700 is waiting
thread 0x48ccf700 is waiting
thread 0x484ce700 will exit
thread 0x474cc700 will exit
thread 0x47ccd700 will exit
thread 0x48ccf700 will exit
C语言源代码如下#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<pthread.h>
#include<assert.h>
#include<mysql.h>typedef struct worker
{
void *(*process)(void *arg);
void *arg;
struct worker *next;
}CThread_worker;typedef struct
{
pthread_mutex_t queue_lock;
pthread_cond_t queue_ready; CThread_worker *queue_head; int shutdown;
pthread_t *threadid;
int max_thread_num;
int cur_queue_size;
}CThread_pool;int pool_add_worker(void *(*process)(void *arg),void *arg);
void *thread_routine(void *arg);static CThread_pool *pool=NULL;
void
pool_init(int max_thread_num)
{
pool=(CThread_pool*)malloc(sizeof(CThread_pool)); pthread_mutex_init(&(pool->queue_lock),NULL);
pthread_cond_init(&(pool->queue_ready),NULL);

pool->queue_head=NULL; pool->max_thread_num=max_thread_num;
pool->cur_queue_size=0; pool->shutdown=0; pool->threadid=(pthread_t*)malloc(max_thread_num*sizeof(pthread_t));
int i=0;
for(i=0;i<max_thread_num;i++)
{
pthread_create(&(pool->threadid[i]),NULL,thread_routine,NULL);
}
}
int
pool_add_worker(void *(*process)(void *arg),void *arg)
{
CThread_worker *newworker=(CThread_worker*)malloc(sizeof(CThread_worker));
newworker->process=process;
newworker->arg=arg;
newworker->next=NULL; pthread_mutex_lock(&(pool->queue_lock)); CThread_worker *member=pool->queue_head;
if(member!=NULL)
{
while(member->next!=NULL)
  member=member->next;
member->next=newworker;
}
else
{
pool->queue_head=newworker;
}
assert(pool->queue_head!=NULL); pool->cur_queue_size++;
pthread_mutex_unlock(&(pool->queue_lock)); pthread_cond_signal(&(pool->queue_ready));
return 0;
}
int
pool_destroy()
{
if(pool->shutdown)
  return -1;
pool->shutdown=1; pthread_cond_broadcast(&(pool->queue_ready)); int i;
for(i=0;i<pool->max_thread_num;i++)
  pthread_join(pool->threadid[i],NULL);
free(pool->threadid); CThread_worker *head=NULL;
while(pool->queue_head!=NULL)
{
head=pool->queue_head;
pool->queue_head=pool->queue_head->next;
free(head);
}
pthread_mutex_destroy(&(pool->queue_lock));
pthread_cond_destroy(&(pool->queue_ready)); free(pool);
return 0;
}
void *
thread_routine(void *arg)
{
printf("starting thread 0x%x\n",pthread_self());
while(1)
{
pthread_mutex_lock(&(pool->queue_lock));
while(pool->cur_queue_size==0&&!pool->shutdown)
{
printf("thread 0x%x is waiting\n",pthread_self());
pthread_cond_wait(&(pool->queue_ready),&(pool->queue_lock));
}
if(pool->shutdown)
{
pthread_mutex_unlock(&(pool->queue_lock));
printf("thread 0x%x will exit\n",pthread_self());
pthread_exit(NULL);
}
printf("thread 0x%x is starting to work\n",pthread_self()); assert(pool->cur_queue_size!=0);
assert(pool->queue_head!=NULL); pool->cur_queue_size--;
CThread_worker *worker=pool->queue_head;
pool->queue_head=worker->next;
pthread_mutex_unlock(&(pool->queue_lock)); (*(worker->process))(worker->arg);
free(worker);
worker=NULL;
}
pthread_exit(NULL);
}void *
myprocess(void *arg)
{
printf("threadid is 0x%x,working on task %d\n",pthread_self(),*(int *)arg); MYSQL mysql;
mysql_init(&mysql);
if(!mysql_real_connect(&mysql,"127.0.0.1","","","test",0,NULL,0))
{
printf("connect failed\n");
printf("%d:%s\n",mysql_errno(&mysql),mysql_error(&mysql));
}
int res=mysql_query(&mysql,"insert into test1 values('','b','0')");
if(res!=0)
{
printf("insert failed\n");
}
mysql_close(&mysql); sleep(1);
return NULL;
}
int main(int argc,char **argv)
{
pool_init(3); int *workingnum=(int *)malloc(sizeof(int)*10);
int i;
for(i=0;i<10;i++)
{
workingnum[i]=i;
pool_add_worker(myprocess,&workingnum[i]);
}
sleep(5);
pool_destroy();
free(workingnum);
return 0;
}