Annotation of prex/usr/sample/sem/sem.c, Revision 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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