Linux下的C语言编程

逃离我推掉我的手 2022-07-14 00:52 200阅读 0赞

计算有名管道中读入及写入的字节数

#include <stdio.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <errno.h>
    #include <fcntl.h>
    #include <stdlib.h>
    #include <memory.h>
    
    #define FIFO_SEVER "/tmp/fifosever"
    
    int main(int argc,char **argv)
    {
        char r_buf[4096*2];
        int fd;
        int r_size;
        int ret_size;
        r_size = atoi(argv[1]);
        printf("requore real read bytes %d\n",r_size);
        memset(r_buf,0,sizeof(r_buf));
        fd = open (FIFO_SEVER,O_RDONLY|O_NONBLOCK);
        if(fd == -1)
        {
            printf("open %s for read error!\n");
            exit(0);
        }
        while(1)
        {
            memset(r_buf,0,sizeof(r_buf));
            ret_size = read(fd,r_buf,r_size);
            if(ret_size == -1)
            {
                if(errno == EAGAIN)
                    printf("no data avalible\n");
            }
            printf("real read bytes %d\n",ret_size);
            sleep(1);
        }
        pause();
        unlink(FIFO_SEVER);
    
        return 0;
    }

#include <stdio.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <errno.h>
    #include <fcntl.h>
    #include <memory.h>
    #include <stdlib.h>
    
    #define FIFO_SEVER "/tmp/fifosever"
    
    int main(int argc,char *argv[])
    {
        int fd;
        char w_buf[4096*2];
        int real_wnum;
        
        memset(w_buf,0,4096*2);
    
        if((mkfifo(FIFO_SEVER,O_CREAT|O_EXCL) < 0) && (errno != EEXIST))
        {
            printf("cannt create fifosever!\n");
            exit(0);
        }
        fd = open(FIFO_SEVER,O_WRONLY|O_NONBLOCK);
        if(fd == -1)
        {
            if(errno == ENXIO)
                printf("open error,no reading process\n");
        }
        scanf("%s",w_buf);
        real_wnum = write(fd,w_buf,2048);
        if(real_wnum == -1)
        {
            if(errno == EAGAIN)
            {
                printf("write to fifo error try later!\n");
            }
        }
        else
        {
            printf("real write num is %d\n",real_wnum);
        }
    
        return 0;
    }