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Annotation of prex-old/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: }