Is possible to use nanosleep in a infinite loop with select()?

I have a C program that do recv/send operations from/to socket using a for(;;) loop and a select() to monitor the file descriptor. I need also this program to send a packet every 80msec to a packet, how can I implement this? Maybe I can use a fork() and the child process simply write an ack in one of the file descriptor monitored by the select() every 80msec. Is there better solutions?

When calling select() you can use the timeout argument to limit the selection waiting time.

 struct timeval {
           long    tv_sec;         /* seconds */
           long    tv_usec;        /* microseconds */
       };

int select(int nfds, fd_set *readfds, fd_set *writefds,
              fd_set *exceptfds, struct timeval *timeout);

It is rather easy to limit the timeout to 80msec and send the required packet.