linux下使用线程锁互斥访问资源

pthread_mutex_t g_Mutex;

  1 #include <stdio.h>
  2 #include <string.h>
  3 #include <pthread.h>
  4 #include <stdlib.h>
  5 #include <unistd.h>
  6 #include <errno.h>
  7 #include <signal.h>
  8 
  9 #define READ_TIME    20000
 10 #define WRITE_TIME    30000
 11 
 12 pthread_mutex_t g_Mutex;
 13 int g_iX = 0;
 14 int g_rwok = 0;
 15 
 16 bool bExit = false;
 17 
 18 void sig(int signal)
 19 {
 20     bExit = true;
 21 }
 22 
 23 /* writer pthread, write per 30000 us */
 24 void * writer(void * arg)
 25 {
 26     while(1)
 27     {
 28         if(true == bExit)
 29         {
 30             g_rwok++;
 31             break;
 32         }
 33         if(EBUSY != pthread_mutex_trylock(&g_Mutex))
 34         {
 35             printf("\033[0;32mwriter : lock, write begin\033[0m\n");
 36             g_iX = 1;
 37             usleep(WRITE_TIME);
 38             pthread_mutex_unlock(&g_Mutex);
 39             printf("\033[0;32mwriter : write ok, unlock\033[0m\n");
 40         }
 41         else
 42         {
 43             printf("\033[0;32mwriter : \033[0;31mbusy , can not write\033[0m\n");
 44         }
 45         usleep(WRITE_TIME);
 46     }
 47 
 48     return NULL;
 49 }
 50 
 51 /* reader pthread, read per 20000 us */
 52 void * reader(void * arg)
 53 {
 54     while(1)
 55     {
 56         if(true == bExit)
 57         {
 58             g_rwok++;
 59             break;
 60         }
 61         if(EBUSY != pthread_mutex_trylock(&g_Mutex))
 62         {
 63             printf("\033[0;33mreader : lock\033[0m\n");
 64             g_iX = 0;
 65             usleep(READ_TIME);
 66             pthread_mutex_unlock(&g_Mutex);
 67             printf("\033[0;33mreader : unlock , read ok\033[0m\n");
 68         }
 69         else
 70         {
 71             printf("\033[0;33mreader : \033[0;31mbusy , can not read\033[0m\n");
 72         }
 73         usleep(READ_TIME);
 74     }
 75 
 76     return NULL;
 77 }
 78 
 79 int main(int argc, char *argv[])
 80 {
 81     signal(SIGINT, sig);
 82     memset(&g_Mutex, sizeof(g_Mutex), 0);
 83     pthread_mutex_init(&g_Mutex, NULL);
 84     
 85     pthread_t preader, pwriter;
 86     pthread_create(&preader, NULL, reader, NULL);
 87     pthread_create(&pwriter, NULL, writer, NULL);
 88     while(1)
 89     {
 90         if(true == bExit && 2 == g_rwok)
 91         {
 92             break;
 93         }
 94         usleep(100000);
 95     }
 96     pthread_mutex_destroy(&g_Mutex);
 97     printf("\033[0;33mdestroy mutex\033[0m\n");
 98 
 99     return 0;
100 }

reader : lock
writer : busy , can not write
reader : unlock , read ok
writer : lock, write begin
reader : busy , can not read
writer : write ok, unlock
reader : lock
reader : unlock , read ok
writer : lock, write begin
reader : busy , can not read
writer : write ok, unlock