.\" Copyright 2016, Michael Kerrisk <mtk.manpages@gmail.com>
.\" Copyright 2016, Eugene Syromyatnikov <evgsyr@gmail.com>
.\" A very few fragments remain from an earlier version of this page
.\" written by David Howells (dhowells@redhat.com)
.\" Copyright 2024, Alejandro Colomar <alx@kernel.org>
.\"
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.\"
.TH KEYCTL_CLEAR 2const 2024-08-21 "Linux man-pages 6.10"
.SH NAME
KEYCTL_CLEAR
\-
clear a keyring
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <linux/keyctl.h>" "  /* Definition of " KEY* " constants */"
.BR "#include <sys/syscall.h>" "   /* Definition of " SYS_* " constants */"
.B #include <unistd.h>
.P
.BI "long syscall(SYS_keyctl, KEYCTL_CLEAR, key_serial_t " key );
.fi
.SH DESCRIPTION
Clear the contents of (i.e., unlink all keys from) a keyring.
.P
The ID of the key
(which must be of keyring type)
.\" or the error ENOTDIR results
is provided in
.IR key .
.\" According to Documentation/security/keys.txt:
.\"     This function can also be used to clear special kernel keyrings if they
.\"     are appropriately marked if the user has CAP_SYS_ADMIN capability.  The
.\"     DNS resolver cache keyring is an example of this.
.P
The caller must have
.I write
permission on the keyring.
.SH RETURN VALUE
On success,
0 is returned.
.P
On error, \-1 is returned, and
.I errno
is set to indicate the error.
.SH VERSIONS
A wrapper is provided in the
.I libkeyutils
library:
.BR keyctl_clear (3).
.SH STANDARDS
Linux.
.SH HISTORY
Linux 2.6.10.
.SH SEE ALSO
.BR keyctl (2),
.BR keyctl_clear (3)