Based on the type of I/O selected, the function fdopen() instantiates one of the IOBase derived classes and returns the object. For example, when text I/O is selected the function returns an instance of TextIOWrapper. If binary I/O is selected the function returns an instance of FileIO.
The behaviour is the same as that of the built-in function open(). While the built-in function open() creates and returns the the required file object using a file path, the function fdopen() constructs the file object using a file descriptor.
A file descriptor can be created using functions like os.open().
# Example Python program that creates a
# Open a file and get the file descriptor
# Create a file object from the file descriptor
# Append text
# Read the contents back and print
# Read and print the file contents