MLOCKALL(3C) Standard C Library Functions MLOCKALL(3C)

NAME

mlockall, munlockall - lock or unlock address space

SYNOPSIS

#include <sys/mman.h>

int mlockall(int flags);


int munlockall(void);

DESCRIPTION

The mlockall() function locks in memory all pages mapped by an address
space.


The value of flags determines whether the pages to be locked are those
currently mapped by the address space, those that will be mapped in the
future, or both:

MCL_CURRENT Lock current mappings
MCL_FUTURE Lock future mappings


If MCL_FUTURE is specified for mlockall(), mappings are locked as they
are added to the address space (or replace existing mappings), provided
sufficient memory is available. Locking in this manner is not persistent
across the exec family of functions (see exec(2)).


Mappings locked using mlockall() with any option may be explicitly
unlocked with a munlock() call (see mlock(3C)).


The munlockall() function removes address space locks and locks on
mappings in the address space.


All conditions and constraints on the use of locked memory that apply to
mlock(3C) also apply to mlockall().


Locks established with mlockall() are not inherited by a child process
after a fork(2) call, and are not nested.

RETURN VALUES

Upon successful completion, the mlockall() and munlockall() functions
return 0. Otherwise, they return -1 and set errno to indicate the
error.

ERRORS

The mlockall() and munlockall() functions will fail if:

EAGAIN
Some or all of the memory in the address space could not be
locked due to sufficient resources. This error condition
applies to mlockall() only.


EINVAL
The flags argument contains values other than MCL_CURRENT and
MCL_FUTURE.


EPERM
The {PRIV_PROC_LOCK_MEMORY} privilege is not asserted in the
effective set of the calling process.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO

exec(2), fork(2), memcntl(2), mmap(2), mlock(3C), plock(3C), sysconf(3C),
attributes(7), standards(7)

March 22, 2004 MLOCKALL(3C)