int ioperm(unsigned long from, unsigned long num, int turn_on);
sets the port access permission bits for the calling process for
num bytes starting from port address from to the value
If turn_on is nonzero, the calling process must be privileged
Only the first 0x3ff I/O ports can be specified in this manner.
For more ports, the
system call must be used.
Permissions are not inherited by the child created by
Permissions are preserved across
this is useful for giving port access permissions to unprivileged
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
is set appropriately.
Invalid values for
(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 be portable.
Libc5 treats it as a system call and has a prototype in
Glibc1 does not have a prototype.
Glibc2 has a prototype both in
Avoid the latter, it is available on i386 only.