capng_set_rootid - Man Page
set namespace root id
Synopsis
#include <cap-ng.h>
int capng_set_rootid(uid_t rootid);
Description
capng_set_rootid sets the root user ID for file capabilities operations. The value is host-endian and relative to the caller's user namespace. Pass CAPNG_UNSET_ROOTID to clear a previously selected namespace root ID and go back to writing regular V2 file capabilities. Other values select V3 file capabilities; the kernel validates and maps the user ID when the capabilities are written.
Return Value
On success, it returns 0. It returns -1 if there is an internal error or the kernel headers used to build the library do not support V3 file capabilities.
See Also
Author
Steve Grubb
Info
March 2026 Red Hat Libcap-ng API