pipe - demo

/*
pipe-write
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <sys/types.h>
       #include <sys/stat.h>
       #include <fcntl.h>
#include <errno.h>

/*
* if do write first, write-app will be blocked until read-app start.
* in runtime, when read-app closed, then write-app will be receive signal(SIGPIPE), and then terminate self.
*/

#define FIFO_FFPLAY        "/tmp/my_fifo"

int main()
{
    int fd = mkfifo(FIFO_FFPLAY, 0777);
    if (fd == 0) {
        printf("create FIFO OK.\n");
    }
    else {
        if (EEXIST != errno) {
            printf("mkfifo failed. \n");
            exit(-1);
        }
    }

    fd = open(FIFO_FFPLAY, O_WRONLY);
    if (fd < 0) {
        printf("open FIFO failed. \n");
        exit(-1);
    }

    printf("Write data to FIFO.\n");

    char line[128] = {0};
    int idx = 0;
    while (1) {
        sprintf(line, "%04d.\n 000", idx++);
        printf(line);
        write(fd, line, strlen(line));
        usleep(1000000);
    }

    close(fd);
    //unlink(FIFO_FFPLAY);

    return 0;
}

/*
pipe-read
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <sys/types.h>
       #include <sys/stat.h>
       #include <fcntl.h>
#include <errno.h>

#define FIFO_FFPLAY        "/tmp/my_fifo"

int main()
{
    int fd = mkfifo(FIFO_FFPLAY, 0777);
    if (fd == 0) {
        printf("create FIFO OK.\n");
    }
    else {
        if (EEXIST != errno) {
            printf("mkfifo failed. \n");
            exit(-1);
        }
    }

    fd = open(FIFO_FFPLAY, O_RDONLY);
    if (fd < 0) {
        printf("open FIFO failed. \n");
        exit(-1);
    }

    FILE *file = fdopen(fd, "r");
    printf("reading data from FIFO.\n");

    char line[128] = {0};
    errno = 0;
    while (1) {
        if (fgets(line, 127, file)) {
        //if (read(fd, line, 127) > 0) {
            printf("### [%s] ###\n", line);
        }
        usleep(100000);
    }

    close(fd);
    //unlink(FIFO_FFPLAY);

    return 0;
}