.\" Copyright, the authors of the Linux man-pages project .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" .TH ioctl_nsfs 2 (date) "Linux man-pages (unreleased)" .SH NAME ioctl_nsfs \- ioctl() operations for Linux namespaces .SH SYNOPSIS .nf .BR "#include " " /* Definition of " NS_* " constants */" .B #include .P .BI "int ioctl(int " fd ", unsigned long " op ", ...);" .fi .SH DESCRIPTION .SS Discovering namespace relationships .TP .BR NS_GET_USERNS (2const) .TQ .BR NS_GET_PARENT (2const) .SS Discovering the namespace type .TP .BR NS_GET_NSTYPE (2const) .SS Discovering the owner of a user namespace .TP .BR NS_GET_OWNER_UID (2const) .SH ERRORS .TP .B ENOTTY .I fd does not refer to a .IR /proc/ pid /ns/ * file. .SH STANDARDS Linux. .SH SEE ALSO .BR ioctl (2), .BR fstat (2), .BR proc (5), .BR namespaces (7)