Output redirection using fork() and execl()

Question

I want to use fork() to spawn off a new process in my program. The new process will have only one task: To redirect the mouse input to a serial port. I have tested the follo

Answer 1

You cannot perform redirection in this way.

If you want to redirect stdout for a process you're about to exec, you need to open the path and dup2 it onto the appropriate file descriptor.

Example:

 if (!(pid = fork()) 
 {
     int fd = open("/dev/ttyS0", O_WRONLY);
     dup2(fd, 1);  // redirect stdout
     execl("/usr/bin/hexdump", "hexdump", "/dev/input/mice", NULL);
 }