.\" Hey Emacs! This file is -*- nroff -*- source. .\" .\" Copyright (c) 1993 Michael Haardt .\" (u31b3hs@pool.informatik.rwth-aachen.de) .\" Fri Apr 2 11:32:09 MET DST 1993 .\" .\" This is free documentation; you can redistribute it and/or .\" modify it under the terms of the GNU General Public License as .\" published by the Free Software Foundation; either version 2 of .\" the License, or (at your option) any later version. .\" .\" The GNU General Public License's references to "object code" .\" and "executables" are to be interpreted as the output of any .\" document formatting or typesetting system, including .\" intermediate and printed output. .\" .\" This manual is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the .\" GNU General Public License for more details. .\" .\" You should have received a copy of the GNU General Public .\" License along with this manual; if not, write to the Free .\" Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, .\" USA. .\" .\" Modified Sat Jul 24 15:12:05 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Tue Aug 1 16:27 1995 by Jochen Karrer .\" (cip307@cip.physik.uni-wuerzburg.de) .\" .TH IOPERM 2 "January 21, 1993" "Linux" "Linux Programmer's Manual" .SH NAME ioperm \- set port input/output permissions .SH SYNOPSIS .B #include .sp .BI "int ioperm(unsigned long " from ", unsigned long " num ", int " turn_on ); .SH DESCRIPTION \fBIoperm\fP sets the port access permission bits for the process for \fInum\fP bytes starting from port address \fBfrom\fP to the value \fBturn_on\fP. The use of \fBioperm\fP require root privileges. Only the first 0x3ff I/O ports can be specified in this manner. For more ports, the .B iopl function must be used. Permissions are not inherited on fork, but on exec they are. This is useful for giving port access permissions to non privileged tasks. .SH "RETURN VALUE" On success, zero is returned. On error, \-1 is returned, and .I errno is set appropriately. .SH "CONFORMING TO" \fBioperm\fP is Linux specific. .SH "SEE ALSO" .BR iopl (2)