linux 互斥锁之trylock的简单测试

  

   /*
    ************************************************************************
 * Filename: n_trylock.c
 * Description: 
 * Version: 1.0
 * Created: 2011骞?4鏈?2鏃?20鏃?9鍒?2绉?
 * Revision: none
 * Compiler: gcc
 * Author: wenhao (wh), [email protected]
 * Company: sunplusapp
 * ***********************************************************************
   */
   


#include 
   <
   stdio.h
   >
   
#include 
   <
   pthread.h
   >
   
#include 
   <
   errno.h
   >
   
pthread_mutex_t mutex;


   void
    
   *
   thread_a(
   void
    
   *
   arg)
{
 printf(
   "
   thread a enter\n
   "
   );
 pthread_mutex_lock(
   &
   mutex);
 printf(
   "
   mutex a lock\n
   "
   );
 sleep(
   6
   );
 pthread_mutex_unlock(
   &
   mutex);
 printf(
   "
   mutex a unlock\n
   "
   );
}


   void
    
   *
   thread_b(
   void
    
   *
   arg)
{
 printf(
   "
   thread b enter\n
   "
   );

   #if
    1
   
 pthread_mutex_trylock(
   &
   mutex);

   #else
   
 
   while
   (pthread_mutex_trylock(
   &
   mutex)
   ==
   EBUSY)
 {
 printf(
   "
   pthread b trylock\n
   "
   );
 sleep(
   1
   );
 }

   #endif
   
 printf(
   "
   mutex b lock\n
   "
   );
 pthread_mutex_unlock(
   &
   mutex);
 printf(
   "
   mutex b unlock\n
   "
   );
}


   int
    main(
   int
    argc,
   char
    
   **
   argv)
{
 pthread_t tid_a,tid_b;
 
   int
    err;

 
   if
   (pthread_mutex_init(
   &
   mutex,NULL) 
   !=
    
   0
   )
 {
 perror(
   "
   pthread_mutex_init
   "
   );

 }

 err 
   =
    pthread_create(
   &
   tid_a,NULL,thread_a,NULL);
 
   if
   (err 
   !=
    
   0
   )
 {
 perror(
   "
   pthread_create thread_a
   "
   );
 }

 sleep(
   1
   );
 err 
   =
    pthread_create(
   &
   tid_b,NULL,thread_b,NULL);
 
   if
   (err 
   <
    
   0
   )
 {
 perror(
   "
   pthread_create thread_b
   "
   );
 }
 sleep(
   10
   );

 printf(
   "
   the main close\n
   "
   );

 
   return
    
   0
   ;
}