2.11BSD/src/man/man2/fetchi.2

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.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)fetchi.2	2.3 (Berkeley) 1/22/87
.\"
.TH FETCHI 2 "January 22, 1987"
.UC 2
.SH NAME
fetchi \- fetch from user instruction space (2BSD)
.SH SYNOPSIS
.nf
.ft B
fetchi(addr)
int *addr;
.fi
.ft R
.SH DESCRIPTION
.I Fetchi
fetches the word at
.I addr
from the caller's instruction space.
This system call is required
on PDP-11's with separate instruction
and data spaces because the
.I mfpi
instruction reads from
D-space if the current
and previous modes in the
program status word are
both user.
.SH "RETURN VALUE
Upon successful completion the contents of the caller's instruction space at
.I addr
are returned.  Otherwise, a value of \-1 is returned.
.SH "ERRORS
.TP 15
[EINVAL]
The kernel has not been compiled for a processor with separate I/D.
.TP 15
[EFAULT]
.I Addr
points to an address not in the process's allocated instruction space.
.SH BUGS
The error indication, \-1, is a legitimate function value;
.I errno,
(see
.IR intro (2)),
can be used to disambiguate.
.PP
.I Fetchi
is a kludge and exists only to circumvent an alleged
security feature on some DEC PDP-11 processors.
.PP
.I Fetchi
is unique to the PDP-11 and 2BSD; its use is discouraged.