Annotation of prex/usr/sample/sem/sem.c, Revision 1.1.1.1
1.1 nbrk 1: /*
2: * Copyright (c) 2005, Kohsuke Ohtani
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. Neither the name of the author nor the names of any co-contributors
14: * may be used to endorse or promote products derived from this software
15: * without specific prior written permission.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27: * SUCH DAMAGE.
28: */
29:
30: /*
31: * sem.c - sample program for semaphore.
32: */
33:
34: #include <prex/prex.h>
35: #include <stdio.h>
36:
37: static sem_t sem;
38:
39: void
40: thread_run(void (*start)(void), void *stack)
41: {
42: thread_t th;
43:
44: if (thread_create(task_self(), &th) != 0)
45: panic("thread_create is failed");
46:
47: if (thread_load(th, start, stack) != 0)
48: panic("thread_load is failed");
49:
50: if (thread_resume(th) != 0)
51: panic("thread_resume failed");
52:
53: return;
54: }
55:
56: /*
57: * The main routine create 10 copy of this thread. But, since the
58: * initial semaphore value is 3, only 3 threads can run at same time.
59: */
60: static void
61: new_thread(void)
62: {
63: thread_t th;
64:
65: th = thread_self();
66: printf("Start thread=%x\n", (u_int)th);
67: thread_yield();
68:
69: /*
70: * Acquire semaphore
71: */
72: sem_wait(&sem, 0);
73:
74: /*
75: * Sleep 2000 ms
76: */
77: printf("Running thread=%x\n", (u_int)th);
78: timer_sleep(2000, 0);
79:
80: /*
81: * Release semaphore
82: */
83: sem_post(&sem);
84:
85: printf("End thread=%x\n", (u_int)th);
86: thread_terminate(th);
87: }
88:
89: int
90: main(int argc, char *argv[])
91: {
92: static char stack[10][1024];
93: int i;
94:
95: printf("Semaphore sample program\n");
96:
97: /*
98: * Initialize semaphore with initial count 3
99: */
100: sem_init(&sem, 3);
101:
102: /*
103: * Boost the priority of this thread
104: */
105: thread_setprio(thread_self(), 100);
106:
107: /*
108: * Create 10 threads
109: */
110: for (i = 0; i < 10; i++)
111: thread_run(new_thread, stack[i]+1024);
112:
113: /*
114: * Wait...
115: */
116: thread_suspend(thread_self());
117:
118: return 0;
119: }
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