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Annotation of prex-old/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: }