使用 FIFO 实现进程间通信示例

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第一个程序是数据生产者程序。它在需要时创建管道，然后尽可能快地向管道中写入数据。为了方便起见，本程序没有初始化缓冲区。

生产者程序

/*数据生产者*/#include <unistd.h>#include <stdlib.h>#include <stdio.h>#include <string.h>#include <fcntl.h>#include <limits.h>#include <sys/types.h>#include <sys/stat.h>#define FIFO_NAME "/tmp/my_fifo"#define BUFFER_SIZE PIPE_BUF#define TEN_MEG (1024 * 1024 *10 )int main(){    int pipe_fd;    int res;    int open_mode = O_WRONLY;    int bytes_sent = 0;    char buffer[BUFFER_SIZE + 1];    if( -1 == access(FIFO_NAME, F_OK) ) {        res = mkfifo( FIFO_NAME, 0777 );  //创建一个FIFO        if( 0 != res ) {            fprintf( stderr, "Could not create fifo %s\n", FIFO_NAME );            exit( EXIT_FAILURE );        }    }    printf("Process %d opening FIFO O_WRONLY\n", getpid() );    pipe_fd = open( FIFO_NAME, open_mode );    printf("Process %d result %d\n", getpid(), pipe_fd);    if( -1 != pipe_fd ) {        while( bytes_sent < TEN_MEG ) {            res = write( pipe_fd, buffer, BUFFER_SIZE );            if( -1 == res ) {                fprintf( stderr, "Write error on pipe\n");                exit( EXIT_FAILURE );            }            bytes_sent += res;        }        close( pipe_fd );    }    else        exit( EXIT_FAILURE );    printf("Process %d finished\n", getpid() );    exit( EXIT_SUCCESS );}

消费者程序

第二个程序是消费者程序，它从 FIFO 读取数据并丢弃它们。

/*数据消费者*/#include <unistd.h>#include <stdlib.h>#include <stdio.h>#include <string.h>#include <fcntl.h>#include <limits.h>#include <sys/types.h>#include <sys/stat.h>#define FIFO_NAME "/tmp/my_fifo"#define BUFFER_SIZE PIPE_BUFint main(){    int pipe_fd;    int res;    int open_mode = O_RDONLY;    int bytes_read = 0;    char buffer[BUFFER_SIZE + 1];    memset( buffer, '\0', sizeof(buffer) );        printf("Process %d opening FIFO O_RDONLY\n", getpid() );    pipe_fd = open( FIFO_NAME, open_mode );    printf("Process %d result %d\n", getpid(), pipe_fd);    if( -1 != pipe_fd ) {        do {            res = read( pipe_fd, buffer, BUFFER_SIZE );            if( -1 == res ) {                fprintf( stderr, "Write error on pipe\n");                exit( EXIT_FAILURE );            }            bytes_read += res;        }while( res>0 );        close( pipe_fd );    }    else        exit( EXIT_FAILURE );    printf("Process %d finished, %d bytes read\n", getpid(), bytes_read );    exit( EXIT_SUCCESS );}

程序运行结果

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