Example of Semaphore APIs-Synchronization and Communication functions

  1 /*
  2  *        main.c 
  3  *  To demonstrate the use of semaphore related APIs
  4  */
  5 
  6 #include <basic.h>
  7 #include <tk/tkernel.h>
  8 #include <stdio.h>
  9 #ifdef DEBUG
 10 #include <util/tmonitor.h>
 11 #endif
 12 
 13 IMPORT void task1 (INT, VP);
 14 ID taskid1 = -1;
 15 ID taskid2 = -1;
 16 ID sem_id = -1;
 17 
 18 
 19 /*****************************************************************
 20 task1 and task 2 trying to acquire resource
 21 task 1 wait for task 2 before rel sem .
 22  ****************************************************************/
 23 IMPORT void
 24 task1 (INT stacd, VP exinf)
 25 {
 26   int cnt = 0;
 27 
 28   printf ("This is task %d, going for 3 loop\n", taskid1);
 29   while (cnt < 3)
 30     {
 31       printf ("task %d try get semaphore\n", taskid1);
 32       tk_wai_sem (sem_id, 1, TMO_FEVR);
 33       printf ("enter critical section task %d: cnt = %d\n", taskid1, cnt++);
 34       tk_dly_tsk (3000);
 35       printf ("delay task 1 over leave critical section\n");
 36       tk_sig_sem (sem_id, 1);
 37     }
 38   tk_del_sem (sem_id);
 39   printf ("task 1 exit and del task, semaphore now\n");
 40   taskid1 = -1;
 41   sem_id = -1;
 42   tk_exd_tsk ();
 43 }
 44 
 45 
 46 
 47 /*****************************************************************
 48 task1 and task 2 trying to acquire resource
 49  ****************************************************************/
 50 IMPORT void
 51 task2 (INT stacd, VP exinf)
 52 {
 53   int cnt = 0;
 54 
 55   printf ("\tThis is task %d, going for 3 loop\n", taskid2);
 56   while (cnt < 3)
 57     {
 58       printf ("\ttask %d try get semaphore\n", taskid2);
 59       tk_wai_sem (sem_id, 1, TMO_FEVR);
 60       printf ("\tenter critical section task %d: cnt = %d\n", taskid2, cnt++);
 61       tk_dly_tsk (3000);
 62       printf ("\tdelay task 2 over leave critical section\n");
 63       tk_sig_sem (sem_id, 1);
 64     }
 65 
 66   printf ("\ttask 2 exit and del task now\n");
 67   taskid2 = -1;
 68   tk_exd_tsk ();
 69 }
 70 
 71 
 72 /******************************************************************************
 73 main
 74 ******************************************************************************/
 75 EXPORT ER
 76 main (INT ac, UB * av[])
 77 {
 78   T_CTSK ctsk;
 79   T_CSEM sem;
 80 
 81 #ifdef DEBUG
 82   tm_monitor ();
 83 #endif
 84   printf ("main: (ac=%d)\n", ac);
 85 
 86   if (ac < 0)
 87     {
 88       if (taskid1 >= 0)
 89         {
 90           tk_ter_tsk (taskid1);
 91           tk_del_tsk (taskid1);
 92         }
 93       if (taskid2 >= 0)
 94         {
 95           tk_ter_tsk (taskid2);
 96           tk_del_tsk (taskid2);
 97         }
 98       goto ext;
 99     }
100   sem.exinf = (VP) 0x00000000;
101   sem.sematr = TA_TFIFO | TA_FIRST;
102   sem.isemcnt = 1;
103   sem.maxsem = 1;
104   sem_id = tk_cre_sem (&sem);
105   printf ("tk_cre_sem: (sem id = %d)\n", sem_id);
106   if (sem_id < E_OK)
107     goto ext;
108 
109 
110   ctsk.exinf = (VP) 0x74736574;
111   ctsk.tskatr = TA_HLNG | TA_RNG0;
112   ctsk.task = task1;
113   ctsk.itskpri = 80;
114   ctsk.stksz = 1024 * 4;
115   taskid1 = tk_cre_tsk (&ctsk);
116   printf ("tk_cre_tsk: (task1id = %d)\n", taskid1);
117   if (taskid1 < E_OK)
118     {
119       tk_del_sem (sem_id);
120       goto ext;
121     }
122 
123   ctsk.exinf = (VP) 0x74736574;
124   ctsk.tskatr = TA_HLNG | TA_RNG0;
125   ctsk.task = task2;
126   ctsk.itskpri = 80;
127   ctsk.stksz = 1024 * 4;
128   taskid2 = tk_cre_tsk (&ctsk);
129   printf ("tk_cre_tsk: (task2id = %d)\n", taskid2);
130   if (taskid2 < E_OK)
131     {
132       tk_del_sem (sem_id);
133       tk_del_tsk (taskid1);
134       goto ext;
135     }
136 
137   printf ("start tasks now\n");
138   tk_sta_tsk (taskid1, 0);
139   tk_sta_tsk (taskid2, 0);
140   tk_dly_tsk (20000);
141 
142   /*end */
143 ext:
144   printf ("main ended\n\n");
145   return 0;
146 }