Question

I am trying to implement a named PIPE IPC method in which I am sending float values (10) each time the sendToPipe function is being called. Here is the sendToPipe function -

int fd;
char *fifoPipe = "/tmp/fifoPipe";

void sendToPipe(paTestData *data){

    int readCount   = 10;
    fd      = open(fifoPipe, O_WRONLY);   // Getting stuck here

    // Reading 10 sample float values from a buffer from readFromCB pointer as the initial address on each call to sendToPipe function.
    while(readCount > 0){

        write(fd, &data->sampleValues[data->readFromCB], sizeof(SAMPLE));  // SAMPLE is of float datatype
        data->readFromCB++;
        readCount--;
    }

    close(fd);

    //  Some code here
}

And I have initialized the named PIPE in my main here :

int main(){

    // Some code
    mkfifo(fifoPipe, S_IWUSR | S_IRUSR);

    // Other code
}

I am not getting where am I going wrong here. Any help is appreciated. Also let me know if any other information is required.

Answer 1

总结所有评论点：

节目是＆＃34;冻结＆＃34;因为管道的另一边没有读卡器。
第一个程序启动后，管道已创建。下一个程序启动将返回FILE_EXIST错误。
要将一个镜头中的10个值写入管道，使读者能够一次性接收所有这些值，您应该准备一个缓冲区，然后打开管道并写入它（阻塞模式）。作为旁注，请注意读者方：读取功能不允许在镜头中检索整个缓冲区，因此必须检查返回的读取数据编号。

Answer 2

感谢@LPs指出出了什么问题。进入PIPE后我的每个样品都在等待阅读。然而，我想要一个实现，其中我的读者线程可以一次读取所有10个样本。这是我的实施。 -

void pipeData(paTestData *data){

    SAMPLE *tempBuff = (SAMPLE*)malloc(sizeof(SAMPLE)*FRAME_SIZE);
    int readCount   = FRAME_SIZE;

    while(readCount > 0){

        tempBuff[FRAME_SIZE - readCount] = data->sampleValues[data->readFromCB];        
        data->readFromCB++;
        readCount--;
    }

    fd = open(fifoPipe, O_WRONLY);

    write(fd, tempBuff, sizeof(tempBuff));
    // Reader thread called here

    close(fd);
}

Named PIPE is stuck on open

2 个答案: