To share fd between parent and child

Applications Programming
1

i used function fork().
so i made two process.
parent process accepted socket fd and writing to shared memory.
then now. how can child process share parent's socket fd?
is this possible?

Thanks in advance

2

The child inherits all the parent fd, a wonderfully powerful feature even in shell programming, but there is an fcntl flag that closes fd on exec*(), if that is also on your mind. I will google it for you, ging, first hit is good:

open fd close on exec - Google Search