The getwin() function reads window-related data (written earlier by putwin()) from the stdio stream pointed to by filep.
It then creates and initializes a new window using that data.
The putwin() function writes all the data associated with the window pointed to by win to the stdio stream pointed to by filep. The getwin() function can later retrieve this data.
On success, the getwin() function returns a pointer to the new window created. Otherwise, it returns a null pointer.
On success, the putwin() function returns OK. Otherwise, it returns ERR.