Inheritance of File Descriptors
A file descriptor has an “inheritable” flag which indicates if the file descriptor can be inherited by child processes. Since Python 3.4, file descriptors created by Python are non-inheritable by default.
UNIX
On UNIX, non-inheritable file descriptors are closed in child processes at the execution of a new program, other file descriptors are inherited.
os.get_inheritable(fd: int) -> bool
Get the “inheritable” flag of the specified file descriptor (a boolean).
os.set_inheritable(fd: int, inheritable: bool)
Set the “inheritable” flag of the specified file descriptor.
Windows
On Windows, non-inheritable handles and file descriptors are closed in child processes,
except for standard streams (file descriptors 0, 1 and 2: stdin, stdout and stderr),
which are always inherited.
Using spawn* functions, all inheritable handles and all inheritable file descriptors are inherited.
Using the subprocess module, all file descriptors except standard streams are closed,
and inheritable handles are only inherited if the close_fds parameter is False.
os.get_handle_inheritable(handle: int) -> bool
Get the “inheritable” flag of the specified handle (a boolean).
os.set_handle_inheritable(handle: int, inheritable: bool)
Set the “inheritable” flag of the specified handle.