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#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    int data_processed;
    int file_pipes[2];
    const char some_data[] = "123";
    char buffer[BUFSIZ + 1];
    pid_t fork_result;

    memset(buffer, '\0', sizeof(buffer));

    if (pipe(file_pipes) == 0)
    {
        fork_result = fork();
        if (fork_result == -1)
        {
            fprintf(stderr, "Fork failure");
            exit(EXIT_FAILURE);
        }
        /* child */
        if (fork_result == 0)
        {
            sprintf(buffer, "%d", file_pipes[0]);
            (void)execl("pipe4", "pip4", buffer, (char *)0);
            exit(EXIT_FAILURE);
        }
        else
        {
            /* parent */
            data_processed = write(file_pipes[1], some_data,
                                   strlen(some_data));
            printf("%d - Wrote %d bytes\n", getpid(),data_processed);
        }
    }
    exit(EXIT_SUCCESS);
}

子

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[])
{
    int data_processed;
    char buffer[BUFSIZ + 1];
    int file_descriptor;

    memset(buffer, '\0', sizeof(buffer));
    sscanf(argv[1], "%d", &file_descriptor);
    data_processed = read(file_descriptor, buffer, BUFSIZ);

    printf("%d - read %d bytes: %s\n", getpid(), data_processed, buffer);
    exit(EXIT_SUCCESS);
}

30510 - Wrote 3 bytes
30511 - read 3 bytes: 123

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    int data_processed;
    int file_pipes[2];
    const char some_data[] = "123";
    char buffer[BUFSIZ + 1];

    memset(buffer, '\0', sizeof(buffer));

    if (pipe(file_pipes) == 0)
    {
        data_processed = write(file_pipes[1], some_data, strlen(some_data));
        printf("Wrote %d bytes\n", data_processed);
        data_processed = read(file_pipes[0], buffer, BUFSIZ);
        printf("Read %d bytes: %s\n", data_processed, buffer);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    int data_processed;
    int file_pipes[2];
    const char some_data[] = "123";
    char buffer[BUFSIZ + 1];
    pid_t fork_result;

    memset(buffer, '\0', sizeof(buffer));

    if (pipe(file_pipes) == 0)
    {
        fork_result = fork();
        if (fork_result == -1)
        {
            fprintf(stderr, "Fork failure");
            exit(EXIT_FAILURE);
        }
        /* child */
        if (fork_result == 0)
        {
            data_processed = read(file_pipes[0], buffer, BUFSIZ);
            printf("Read %d bytes: %s\n", data_processed, buffer);
            exit(EXIT_SUCCESS);
        }
        else
        {
            /* parent */
            data_processed = write(file_pipes[1], some_data,
                                   strlen(some_data));
            printf("Wrote %d bytes\n", data_processed);
        }
    }
    exit(EXIT_SUCCESS);
}

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    FILE *read_fp;
    char buffer[BUFSIZ + 1];
    int chars_read;
    memset(buffer, '\0', sizeof(buffer));
    read_fp = popen("uname -a", "r");
    if (read_fp != NULL)
    {
        chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp);
        if (chars_read > 0)
        {
            printf("Output was: -\n%s\n", buffer);
        }
        pclose(read_fp);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    FILE *write_fp;
    char buffer[BUFSIZ + 1];

    sprintf(buffer, "Once upon time, there was..\n");
    write_fp = popen("od -c", "w");
    if (write_fp != NULL)
    {
        fwrite(buffer, sizeof(char), strlen(buffer), write_fp);
        pclose(write_fp);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    FILE *read_fp;
    char buffer[BUFSIZ + 1];
    int chars_read;

    memset(buffer, '\0', sizeof(buffer));
    read_fp = popen("ps ax", "r");
    if (read_fp != NULL)
    {
        chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp);
        while (chars_read > 0)
        {
            buffer[chars_read - 1] = '\0';
            printf("Reading %d:-\n %s\n", BUFSIZ, buffer);
            chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp);
        }
        pclose(read_fp);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main()
{
    FILE *read_fp;
    char buffer[BUFSIZ + 1];
    int chars_read;

    memset(buffer, '\0', sizeof(buffer));
    read_fp = popen("cat popen*.c | wc -l", "r");
    if (read_fp != NULL)
    {   
        chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp);
        while (chars_read > 0)
        {
            buffer[chars_read - 1] = '\0';
            printf("Reading:-\n %s\n", buffer);
            chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp);
        }
        pclose(read_fp);
        exit(EXIT_SUCCESS);
    }
    exit(EXIT_FAILURE);
}

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

#define NUM_THREADS 6

void *thread_function(void *arg);

int main()
{
    int res;
    pthread_t a_thread[NUM_THREADS];
    void *thread_result;
    int lots_of_threads;

    for (lots_of_threads = 0; lots_of_threads < NUM_THREADS; lots_of_threads++)
    {
        res = pthread_create(&(a_thread[lots_of_threads]), NULL, 
                             thread_function, (void *)lots_of_threads);
        if (res != 0)
        {
            perror("Thread creation failed");
            exit(EXIT_FAILURE);
        }
    }
    printf("Waiting for threads to finish...\n");
    for (lots_of_threads = NUM_THREADS - 1; lots_of_threads >= 0;
         lots_of_threads--)
    {
        res = pthread_join(a_thread[lots_of_threads], &thread_result);
        if (res == 0)
        {
            printf("Picked up a thread\n");
        }
        else
        {
            perror("pthread_join failed");
        }
    }
    printf("All done\n");
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    int my_number = (int)arg;
    int rand_num;

    printf("thread_function is running. Argument was %d\n", my_number);
    rand_num = 1 + (int) (9.0 * rand() / (RAND_MAX + 1.0));
    sleep(rand_num);
    printf("Bye from %d\n", my_number);
    pthread_exit(NULL);
}

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

void *thread_function(void *arg);

int main()
{
    int res;
    pthread_t a_thread;
    void *thread_result;

    res = pthread_create(&a_thread, NULL, thread_function, NULL);
    if (res != 0)
    {
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }
    sleep(3);
    printf("Canceling thread...\n");
    res = pthread_cancel(a_thread);
    if (res != 0)
    {
        perror("Thread cancelation failed");
        exit(EXIT_FAILURE);
    }
    printf("Waiting for thread to finish...\n");
    res = pthread_join(a_thread, &thread_result);
    if (res != 0)
    {
        perror("Thread join failed");
        exit(EXIT_FAILURE);
    }
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    int i, res;
    res = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
    if (res != 0)
    {
        perror("Thread pthread_setcancelstate failed");
        exit(EXIT_FAILURE);
    }
    res = pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
    if (res != 0)
    {
        perror("Thread pthread_setcanceltype failed");
        exit(EXIT_FAILURE);
    }
    printf("thread_function is running\n");
    for (i = 0; i < 10; i++)
    {
        printf("Thread is still running (%d) ...\n", i);
        sleep(1);
    }
    pthread_exit(0);
}

thread_function is running
Thread is still running (0) ...
Thread is still running (1) ...
Thread is still running (2) ...
Canceling thread...
Waiting for thread to finish...
 

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

void *thread_function(void *arg);

char message[] = "Hello World";
int thread_finished = 0;

int main()
{
    int res;
    pthread_t a_thread;
    pthread_attr_t thread_attr;

    int max_priority;
    int min_priority;
    struct sched_param scheduling_value;

    res = pthread_attr_init(&thread_attr);
    if (res != 0)
    {
        perror("Attribute creation failed");
        exit(EXIT_FAILURE);
    }
    /* 设置调度策略 */
    res = pthread_attr_setschedpolicy(&thread_attr, SCHED_OTHER);
    if (res != 0)
    {
        perror("Setting scheduling policy failed");
        exit(EXIT_FAILURE);
    }

    res = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
    if (res != 0)
    {
        perror("Setting detached attribute failed");
        exit(EXIT_FAILURE);
    }
    res = pthread_create(&a_thread, &thread_attr, 
                         thread_function, (void *)message);
    if (res != 0)
    {
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }
    /* 查找允许的优先级范围 */
    max_priority = sched_get_priority_max(SCHED_OTHER);
    min_priority = sched_get_priority_min(SCHED_OTHER);
    /* 设置优先级 */
    scheduling_value.sched_priority = min_priority;
    res = pthread_attr_setschedparam(&thread_attr, &scheduling_value);
    if (res != 0)
    {
        perror("Setting scheduling priority failed");
        exit(EXIT_FAILURE);
    }
    (void)pthread_attr_destroy(&thread_attr);
    while (!thread_finished)
    {
        printf("Waiting for thread to say it's finished...\n");
        sleep(1);
    }
    printf("Other thread finished, Bye!\n");
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    printf("thread_function is running. Argument was %s\n", (char *)arg);
    sleep(4);
    printf("Second thread setting finished flag, and exiting now\n");
    thread_finished = 1;
    pthread_exit(NULL);
}

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>

void *thread_function(void *arg);

char message[] = "Hello World";
int thread_finished = 0;

int main()
{
    int res;
    pthread_t a_thread;
    pthread_attr_t thread_attr;

    res = pthread_attr_init(&thread_attr);
    if (res != 0)
    {
        perror("Attribute creation failed");
        exit(EXIT_FAILURE);
    }
    res = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
    if (res != 0)
    {
        perror("Setting detached attribute failed");
        exit(EXIT_FAILURE);
    }
    res = pthread_create(&a_thread, &thread_attr, 
                         thread_function, (void *)message);
    if (res != 0)
    {
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }
    (void)pthread_attr_destroy(&thread_attr);
    while (!thread_finished)
    {
        printf("Waiting for thread to say it's finished...\n");
        sleep(1);
    }
    printf("Other thread finished, Bye!\n");
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    printf("thread_function is running. Argument was %s\n", (char *)arg);
    sleep(4);
    printf("Second thread setting finished flag, and exiting now\n");
    thread_finished = 1;
    pthread_exit(NULL);
}

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <semaphore.h>

void *thread_function(void *arg);
pthread_mutex_t work_mutex;

#define WORK_SIZE 1024
char work_area[WORK_SIZE];
int time_to_exit = 0;

int main()
{
    int res;
    pthread_t a_thread;
    void *thread_result;
    res = pthread_mutex_init(&work_mutex, NULL);
    if (res != 0)
    {
        perror("Mutex initialization failed");
        exit(EXIT_FAILURE);
    }
    res = pthread_create(&a_thread, NULL, thread_function, NULL);
    if (res != 0)
    {
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }
    pthread_mutex_lock(&work_mutex);
    printf("Input some text. Enter 'end' to finish\n");
    while (!time_to_exit)
    {
        fgets(work_area, WORK_SIZE, stdin);
        pthread_mutex_unlock(&work_mutex);
        while (1)
        {
            pthread_mutex_lock(&work_mutex);
            if (work_area[0] != '\0')
            {
                pthread_mutex_unlock(&work_mutex);
                sleep(1);
            }
            else
            {
                break;
            }
        }
    }
    pthread_mutex_unlock(&work_mutex);
    printf("\nWaiting for thread to finish...\n");
    res = pthread_join(a_thread, &thread_result);
    if (res != 0)
    {
        perror("Thread join failed");
        exit(EXIT_FAILURE);
    }
    printf("Thread joined\n");
    pthread_mutex_unlock(&work_mutex);
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    sleep(1);
    pthread_mutex_lock(&work_mutex);
    while (strncmp("end", work_area, 3) != 0)
    {
        printf("You input %ld characters\n", strlen(work_area) - 1);
        work_area[0] = '\0';
        pthread_mutex_unlock(&work_mutex);
        sleep(1);
        pthread_mutex_lock(&work_mutex);
        while (work_area[0] == '\0')
        {
            pthread_mutex_lock(&work_mutex);
            sleep(1);
            pthread_mutex_lock(&work_mutex);
        }
    }
    time_to_exit = 1;
    work_area[0] = '\0';
    pthread_mutex_unlock(&work_mutex);
    pthread_exit(0);
}

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
#include <semaphore.h>

void *thread_function(void *arg);
sem_t bin_sem;

#define WORK_SIZE 1024
char work_area[WORK_SIZE];

int main()
{
    int res;
    pthread_t a_thread;
    void *thread_result;

    res = sem_init(&bin_sem, 0, 0);
    if (res != 0)
    {
        perror("Semaphore initialization failed");
        exit(EXIT_FAILURE);
    }
    res = pthread_create(&a_thread, NULL, thread_function, NULL);
    if (res != 0)
    {
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }
    printf("Input some text. Enter 'end' to finish\n");
    while (strncmp("end", work_area, 3) != 0)
    {
        fgets(work_area, WORK_SIZE, stdin);
        sem_post(&bin_sem);
    }
    printf("\nWaiting for thread to finish...\n");
    res = pthread_join(a_thread, &thread_result);
    if (res != 0)
    {
        perror("Thread join failed");
        exit(EXIT_FAILURE);
    }
    printf("Thread joined\n");
    sem_destroy(&bin_sem);
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    sem_wait(&bin_sem);
    while (strncmp("end", work_area, 3) != 0)
    {
        printf("You input %ld characters\n", strlen(work_area) - 1);
        sem_wait(&bin_sem);
    }
    pthread_exit(NULL);
}

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>

void *thread_function(void *arg);

char message[] = "Hello World";

int main()
{
    int res;
    pthread_t a_thread;
    void *thread_result;

    res = pthread_create(&a_thread, NULL, thread_function, (void *)message);

    if (res != 0)
    {
        perror("Thread creation failed");
        exit(EXIT_FAILURE);
    }
    printf("Waiting for thread to finish...\n");
    res = pthread_join(a_thread, &thread_result);
    if (res != 0)
    {
        perror("Thread join failed");
        exit(EXIT_FAILURE);
    }
    printf("Thread joined, it returned %s\n", (char *)thread_result);
    printf("Message is now %s\n", message);
    exit(EXIT_SUCCESS);
}

void *thread_function(void *arg)
{
    printf("thread function is running. Argument was %s\n", (char *)arg);
    sleep(3);
    strcpy(message, "Bye!");
    pthread_exit("Thank you for the CPU time");
}