C : how can I change from file descriptor to FILE struct and vice versa?

Is there any way to change an int file descriptor to a FIL开发者_运维技巧E struct pointer or/and change FILE* to a file descriptor in C?

The function fdopen() returns a new (FILE *) associated with an open file descriptor.

The function fileno() returns the file descriptor associated with an open FILE *.

Use "fileno()" for FILE->int.

Use "fdopen()" for int->FILE.