Thread: Problem with O_NONBLOCK Pipe

Originally Posted by hosseinyounesi

Another question: After closing my program, will the pipe file be deleted? I think no. So why?

Because it's a named file you created. Remove it after you close the handle with unlink().

This is what I tried, and it is working now

read:

Code:

    fd_set rfds;
    int res=0;
    int retval;
    struct timeval tv;
    //////////////////
    FD_ZERO(&rfds);
    
    int pipe_fd = open( FIFO_NAME, O_RDONLY | O_NONBLOCK);

    FD_SET(pipe_fd, &rfds);

    tv.tv_sec = 1;
    tv.tv_usec = 0;
    int nfds = max( pipe_fd,1 ) + 1;
    retval = select(nfds, &rfds, NULL, NULL, &tv);

    if ( retval!=-1 )
    {
        if (FD_ISSET(pipe_fd,&rfds))
            res = read(pipe_fd, &T, sizeof(T));
    }
    close(pipe_fd);

    //Ignore Invalid Messages
    if(res != sizeof(T)) return -1;

write:

Code:

int pipe_fd=0, res=0;
//////////////////
while(1)
{    
    pipe_fd = open ( FIFO_NAME.c_str(), O_WRONLY );
    if ( pipe_fd == -1 )
          cout << "open error" << endl;

    res = write ( pipe_fd, &T, sizeof ( T ) );
    if ( res == -1 )
          cout << "write error" << endl;

    close ( pipe_fd );
    sleep ( 1 );
}

So, there is a select, controlling pipe with FD_ISSET and a sleep. If there is any AMBIGUITY or something is missed, please tell me.

Thanks