1MLOCKALL(3P) POSIX Programmer's Manual MLOCKALL(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 mlockall, munlockall - lock/unlock the address space of a process
13 (REALTIME)
14
16 #include <sys/mman.h>
17 int mlockall(int flags);
19 int munlockall(void);
20
23 The mlockall() function shall cause all of the pages mapped by the
24 address space of a process to be memory-resident until unlocked or
25 until the process exits or execs another process image. The flags argu‐
26 ment determines whether the pages to be locked are those currently
27 mapped by the address space of the process, those that are mapped in
28 the future, or both. The flags argument is constructed from the bit‐
29 wise-inclusive OR of one or more of the following symbolic constants,
30 defined in <sys/mman.h>:
31 MCL_CURRENT
33 Lock all of the pages currently mapped into the address space of
34 the process.
35 MCL_FUTURE
37 Lock all of the pages that become mapped into the address space
38 of the process in the future, when those mappings are estab‐
39 lished.
40 If MCL_FUTURE is specified, and the automatic locking of future map‐
43 pings eventually causes the amount of locked memory to exceed the
44 amount of available physical memory or any other implementation-defined
45 limit, the behavior is implementation-defined. The manner in which the
46 implementation informs the application of these situations is also
47 implementation-defined.
48 The munlockall() function shall unlock all currently mapped pages of
50 the address space of the process. Any pages that become mapped into the
51 address space of the process after a call to munlockall() shall not be
52 locked, unless there is an intervening call to mlockall() specifying
53 MCL_FUTURE or a subsequent call to mlockall() specifying MCL_CURRENT.
54 If pages mapped into the address space of the process are also mapped
55 into the address spaces of other processes and are locked by those pro‐
56 cesses, the locks established by the other processes shall be unaf‐
57 fected by a call by this process to munlockall().
58 Upon successful return from the mlockall() function that specifies
60 MCL_CURRENT, all currently mapped pages of the process' address space
61 shall be memory-resident and locked. Upon return from the munlockall()
62 function, all currently mapped pages of the process' address space
63 shall be unlocked with respect to the process' address space. The mem‐
64 ory residency of unlocked pages is unspecified.
65 The appropriate privilege is required to lock process memory with
67 mlockall().
68
70 Upon successful completion, the mlockall() function shall return a
71 value of zero. Otherwise, no additional memory shall be locked, and the
72 function shall return a value of -1 and set errno to indicate the
73 error. The effect of failure of mlockall() on previously existing locks
74 in the address space is unspecified.
75 If it is supported by the implementation, the munlockall() function
77 shall always return a value of zero. Otherwise, the function shall
78 return a value of -1 and set errno to indicate the error.
79
81 The mlockall() function shall fail if:
82 EAGAIN Some or all of the memory identified by the operation could not
84 be locked when the call was made.
85 EINVAL The flags argument is zero, or includes unimplemented flags.
87 The mlockall() function may fail if:
90 ENOMEM Locking all of the pages currently mapped into the address space
92 of the process would exceed an implementation-defined limit on
93 the amount of memory that the process may lock.
94 EPERM The calling process does not have the appropriate privilege to
96 perform the requested operation.
97 The following sections are informative.
100
102 None.
103
105 None.
106
108 None.
109
111 None.
112
114 exec(), exit(), fork(), mlock(), munmap(), the Base Definitions volume
115 of IEEE Std 1003.1-2001, <sys/mman.h>
116
118 Portions of this text are reprinted and reproduced in electronic form
119 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
120 -- Portable Operating System Interface (POSIX), The Open Group Base
121 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
122 Electrical and Electronics Engineers, Inc and The Open Group. In the
123 event of any discrepancy between this version and the original IEEE and
124 The Open Group Standard, the original IEEE and The Open Group Standard
125 is the referee document. The original Standard can be obtained online
126 at http://www.opengroup.org/unix/online.html .
127IEEE/The Open Group 2003 MLOCKALL(3P)