.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
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.TH PR_CAPBSET_DROP 2const 2025-08-24 "Linux man-pages 6.16"
.SH NAME
PR_CAPBSET_DROP
\-
drop a capability from the calling thread's capability bounding set
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#include <linux/prctl.h>" "  /* Definition of " PR_* " constants */"
.B #include <sys/prctl.h>
.P
.BI "int prctl(PR_CAPBSET_DROP, long " cap );
.fi
.SH DESCRIPTION
Drop the capability specified by
.I cap
from the calling thread's capability bounding set.
Any children of the calling thread will inherit the newly
reduced bounding set.
.SH RETURN VALUE
On success,
0 is returned.
On error, \-1 is returned, and
.I errno
is set to indicate the error.
.SH ERRORS
.TP
.B EINVAL
File capabilities are not enabled in the kernel.
.TP
.B EINVAL
.I cap
does not specify a valid capability.
.TP
.B EPERM
The caller does not have the
.B CAP_SETPCAP
capability.
.SH VERSIONS
A higher-level interface layered on top of this operation is provided in the
.BR libcap (3)
library in the form of
.BR cap_drop_bound (3).
.SH STANDARDS
Linux.
.SH HISTORY
Linux 2.6.25.
.SH SEE ALSO
.BR prctl (2),
.BR PR_CAPBSET_READ (2const),
.BR libcap (3),
.BR cap_drop_bound (3)