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.TH MLOCKALL "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"

.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

\(em lock/unlock the address space of a process

(\fBREALTIME\fP)

.SH SYNOPSIS

.LP

.nf

#include <sys/mman.h>

.P

int mlockall(int \fIflags\fP);

int munlockall(void);

.fi

.SH DESCRIPTION

The

\fImlockall\fR()

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

.IR exec s

another process image. The

.IR flags

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

.IR flags

argument is constructed from the bitwise-inclusive OR of one or more

of the following symbolic constants, defined in

.IR <sys/mman.h> :

.IP MCL_CURRENT 12

Lock all of the pages currently mapped into the address space of the

process.

.IP MCL_FUTURE 12

Lock all of the pages that become mapped into the address space of the

process in the future, when those mappings are established.

.P

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.

.P

The

\fImunlockall\fR()

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\fR()

shall not be locked, unless there is an intervening call to

\fImlockall\fR()

specifying MCL_FUTURE or a subsequent call to

\fImlockall\fR()

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\fR().

.P

Upon successful return from the

\fImlockall\fR()

function that specifies MCL_CURRENT, all currently mapped pages of the

address space of the process shall be memory-resident and locked.

Upon return from the

\fImunlockall\fR()

function, all currently mapped pages of the address space of the process

shall be unlocked with respect to the address space of the process.

The memory residency of unlocked pages is unspecified.

.P

Appropriate privileges are required to lock process memory with

\fImlockall\fR().

.SH "RETURN VALUE"

Upon successful completion, the

\fImlockall\fR()

function shall return a value of zero. Otherwise, no additional memory

shall be locked, and the function shall return a value of \(mi1 and set

.IR errno

to indicate the error. The effect of failure of

\fImlockall\fR()

on previously existing locks in the address space is unspecified.

.P

If it is supported by the implementation, the

\fImunlockall\fR()

function shall always return a value of zero. Otherwise, the function

shall return a value of \(mi1 and set

.IR errno

to indicate the error.

.SH ERRORS

The

\fImlockall\fR()

function shall fail if:

.TP

.BR EAGAIN

Some or all of the memory identified by the operation could not be

locked when the call was made.

.TP

.BR EINVAL

The

.IR flags

argument is zero, or includes unimplemented flags.

.P

The

\fImlockall\fR()

function may fail if:

.TP

.BR 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

.BR EPERM

The calling process does not have appropriate privileges to perform

the requested operation.

.LP

.IR "The following sections are informative."

.SH EXAMPLES

None.

.SH "APPLICATION USAGE"

None.

.SH RATIONALE

None.

.SH "FUTURE DIRECTIONS"

None.

.SH "SEE ALSO"

.IR "\fIexec\fR\^",

.IR "\fIexit\fR\^(\|)",

.IR "\fIfork\fR\^(\|)",

.IR "\fImlock\fR\^(\|)",

.IR "\fImunmap\fR\^(\|)"

.P

The Base Definitions volume of POSIX.1\(hy2008,

.IR "\fB<sys_mman.h>\fP"

.SH COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form

from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology

-- Portable Operating System Interface (POSIX), The Open Group Base

Specifications Issue 7, Copyright (C) 2013 by the Institute of

Electrical and Electronics Engineers, Inc and The Open Group.

(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

Any typographical or formatting errors that appear

in this page are most likely

to have been introduced during the conversion of the source files to

man page format. To report such errors, see

https://www.kernel.org/doc/man-pages/reporting_bugs.html .