ioperm - set port input/output permissions
/* for libc5 */
/* for glibc */
int ioperm(unsigned long from, unsigned long num,
() sets the port access permission bits for the calling process for
bytes starting from port address from
to the value
. If turn_on
is nonzero, the calling process must be
Only the first 0x3ff I/O ports can be specified in this manner. For more ports,
system call must be used.
Permissions are not inherited by the child created by fork(2)
Permissions are preserved across execve(2)
; this is useful for giving
port access permissions to unprivileged programs.
This call is mostly for the i386 architecture. On many other architectures it
does not exist or will always return an error.
On success, zero is returned. On error, -1 is returned, and errno
- Invalid values for from or num.
- (on PowerPC) This call is not supported.
- Out of memory.
- The calling process has insufficient privilege.
() is Linux-specific and should not be used in programs intended to
Libc5 treats it as a system call and has a prototype in <unistd.h>
Glibc1 does not have a prototype. Glibc2 has a prototype both in
and in <sys/perm.h>
. Avoid the latter, it
is available on i386 only.
This page is part of release 3.44 of the Linux man-pages
description of the project, and information about reporting bugs, can be found