View Source: ioperm(2) - Waikato Linux Users Group

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!!NAME
ioperm - set port input/output permissions

!!SYNOPSIS
 __#include <unistd.h>__ /* for libc5 */
 __#include <sys/io.h>__ /* for glibc */

 __int ioperm(unsigned long__ ''from''__, unsigned long__ ''num''__, int__ ''turn_on''__);__

!!DESCRIPTION
ioperm(2) sets the port access permission bits for the process for ''num'' bytes starting from port address __from__ to the value __turn_on__. The use of
ioperm(2) requires root privileges.

Only the first 0x3ff I/O ports can be specified in this manner. For more ports, the iopl(2) 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.

!!RETURN VALUE
On success, zero is returned. On error, -1 is returned, and ''errno'' is set appropriately.

!!CONFORMING TO
ioperm(2) is Linux specific and should not be used in programs intended to be portable.

!!NOTES
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 ''<sys/io.h>'' and
in ''<sys/perm.h>''. Avoid the latter, it is available on i386 only.

!!SEE ALSO
iopl(2)

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Last edited on Thursday, February 20, 2003 11:42:34 pm by PerryLorier

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