1MLOCKALL(P) POSIX Programmer's Manual MLOCKALL(P)
2
6 mlockall, munlockall - lock/unlock the address space of a process
7 (REALTIME)
8
10 #include <sys/mman.h>
11 int mlockall(int flags);
13 int munlockall(void);
14
17 The mlockall() function shall cause all of the pages mapped by the
18 address space of a process to be memory-resident until unlocked or
19 until the process exits or execs another process image. The flags argu‐
20 ment determines whether the pages to be locked are those currently
21 mapped by the address space of the process, those that are mapped in
22 the future, or both. The flags argument is constructed from the bit‐
23 wise-inclusive OR of one or more of the following symbolic constants,
24 defined in <sys/mman.h>:
25 MCL_CURRENT
27 Lock all of the pages currently mapped into the address space of
28 the process.
29 MCL_FUTURE
31 Lock all of the pages that become mapped into the address space
32 of the process in the future, when those mappings are estab‐
33 lished.
34 If MCL_FUTURE is specified, and the automatic locking of future map‐
37 pings eventually causes the amount of locked memory to exceed the
38 amount of available physical memory or any other implementation-defined
39 limit, the behavior is implementation-defined. The manner in which the
40 implementation informs the application of these situations is also
41 implementation-defined.
42 The munlockall() function shall unlock all currently mapped pages of
44 the address space of the process. Any pages that become mapped into the
45 address space of the process after a call to munlockall() shall not be
46 locked, unless there is an intervening call to mlockall() specifying
47 MCL_FUTURE or a subsequent call to mlockall() specifying MCL_CURRENT.
48 If pages mapped into the address space of the process are also mapped
49 into the address spaces of other processes and are locked by those pro‐
50 cesses, the locks established by the other processes shall be unaf‐
51 fected by a call by this process to munlockall().
52 Upon successful return from the mlockall() function that specifies
54 MCL_CURRENT, all currently mapped pages of the process' address space
55 shall be memory-resident and locked. Upon return from the munlockall()
56 function, all currently mapped pages of the process' address space
57 shall be unlocked with respect to the process' address space. The mem‐
58 ory residency of unlocked pages is unspecified.
59 The appropriate privilege is required to lock process memory with
61 mlockall().
62
64 Upon successful completion, the mlockall() function shall return a
65 value of zero. Otherwise, no additional memory shall be locked, and the
66 function shall return a value of -1 and set errno to indicate the
67 error. The effect of failure of mlockall() on previously existing locks
68 in the address space is unspecified.
69 If it is supported by the implementation, the munlockall() function
71 shall always return a value of zero. Otherwise, the function shall
72 return a value of -1 and set errno to indicate the error.
73
75 The mlockall() function shall fail if:
76 EAGAIN Some or all of the memory identified by the operation could not
78 be locked when the call was made.
79 EINVAL The flags argument is zero, or includes unimplemented flags.
81 The mlockall() function may fail if:
84 ENOMEM Locking all of the pages currently mapped into the address space
86 of the process would exceed an implementation-defined limit on
87 the amount of memory that the process may lock.
88 EPERM The calling process does not have the appropriate privilege to
90 perform the requested operation.
91 The following sections are informative.
94
96 None.
97
99 None.
100
102 None.
103
105 None.
106
108 exec() , exit() , fork() , mlock() , munmap() , the Base Definitions
109 volume of IEEE Std 1003.1-2001, <sys/mman.h>
110
112 Portions of this text are reprinted and reproduced in electronic form
113 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
114 -- Portable Operating System Interface (POSIX), The Open Group Base
115 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
116 Electrical and Electronics Engineers, Inc and The Open Group. In the
117 event of any discrepancy between this version and the original IEEE and
118 The Open Group Standard, the original IEEE and The Open Group Standard
119 is the referee document. The original Standard can be obtained online
120 at http://www.opengroup.org/unix/online.html .
121IEEE/The Open Group 2003 MLOCKALL(P)