.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "MLOCKALL" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" mlockall 
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.SH NAME
mlockall, munlockall \- lock/unlock the address space of a process
(\fBREALTIME\fP)
.SH SYNOPSIS
.LP
\fB#include <sys/mman.h>
.br
.sp
int mlockall(int\fP \fIflags\fP\fB);
.br
int munlockall(void); \fP
\fB
.br
\fP
.SH DESCRIPTION
.LP
The \fImlockall\fP() function shall cause all of the pages mapped
by the address space of a process to be memory-resident until
unlocked or until the process exits or \fIexec\fPs another process
image. The \fIflags\fP
argument determines whether the pages to be locked are those currently
mapped by the address space of the process, those that are
mapped in the future, or both. The \fIflags\fP argument is constructed
from the bitwise-inclusive OR of one or more of the
following symbolic constants, defined in \fI<sys/mman.h>\fP:
.TP 7
MCL_CURRENT
Lock all of the pages currently mapped into the address space of the
process.
.TP 7
MCL_FUTURE
Lock all of the pages that become mapped into the address space of
the process in the future, when those mappings are
established.
.sp
.LP
If MCL_FUTURE is specified, and the automatic locking of future mappings
eventually causes the amount of locked memory to exceed
the amount of available physical memory or any other implementation-defined
limit, the behavior is implementation-defined. The
manner in which the implementation informs the application of these
situations is also implementation-defined.
.LP
The \fImunlockall\fP() function shall unlock all currently mapped
pages of the address space of the process. Any pages that
become mapped into the address space of the process after a call to
\fImunlockall\fP() shall not be locked, unless there is an
intervening call to \fImlockall\fP() specifying MCL_FUTURE or a subsequent
call to \fImlockall\fP() specifying MCL_CURRENT. If
pages mapped into the address space of the process are also mapped
into the address spaces of other processes and are locked by
those processes, the locks established by the other processes shall
be unaffected by a call by this process to
\fImunlockall\fP().
.LP
Upon successful return from the \fImlockall\fP() function that specifies
MCL_CURRENT, all currently mapped pages of the
process' address space shall be memory-resident and locked. Upon return
from the \fImunlockall\fP() function, all currently mapped
pages of the process' address space shall be unlocked with respect
to the process' address space. The memory residency of unlocked
pages is unspecified.
.LP
The appropriate privilege is required to lock process memory with
\fImlockall\fP().
.SH RETURN VALUE
.LP
Upon successful completion, the \fImlockall\fP() function shall return
a value of zero. Otherwise, no additional memory shall
be locked, and the function shall return a value of -1 and set \fIerrno\fP
to indicate the error. The effect of failure of
\fImlockall\fP() on previously existing locks in the address space
is unspecified.
.LP
If it is supported by the implementation, the \fImunlockall\fP() function
shall always return a value of zero. Otherwise, the
function shall return a value of -1 and set \fIerrno\fP to indicate
the error.
.SH ERRORS
.LP
The \fImlockall\fP() function shall fail if:
.TP 7
.B EAGAIN
Some or all of the memory identified by the operation could not be
locked when the call was made.
.TP 7
.B EINVAL
The \fIflags\fP argument is zero, or includes unimplemented flags.
.sp
.LP
The \fImlockall\fP() function may fail if:
.TP 7
.B ENOMEM
Locking all of the pages currently mapped into the address space of
the process would exceed an implementation-defined limit on
the amount of memory that the process may lock.
.TP 7
.B EPERM
The calling process does not have the appropriate privilege to perform
the requested operation.
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
None.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIexec\fP(), \fIexit\fP(), \fIfork\fP(), \fImlock\fP(), \fImunmap\fP(),
the Base
Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<sys/mman.h>\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .