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HP-UX 11i Version 3: February 2007

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munlockall() — unlock the entire virtual address space of a process


#include <sys/mman.h>

int munlockall();


The munlockall() system call allows the calling process to unlock any portions of its virtual address space that have previously been locked into memory with mlock() or mlockall(), including any portions locked due to the MCL_FUTURE option of mlockall(). Upon successful completion of the munlockall(), all pages within the process virtual address space are subject to routine paging and/or swapping and the MCL_FUTURE option will no longer be in effect for the process.

Regardless of how many times a process locks a page, a single munlockall() will unlock it. When memory is shared by multiple processes and mlocks are applied to the same physical page by multiple processes, a page remains locked until the last lock is removed from that page.

The effective user ID of the calling process must be a user with the MLOCK privilege.

Although plock() and the mlock() family of functions may be used together in an application, each may affect the other in unexpected ways. This practice is not recommended.

Security Restrictions

Some or all of the actions associated with this system call require the MLOCK privilege. Processes owned by the superuser have this privilege. Processes owned by other users may have this privilege, depending on system configuration. See privileges(5) for more information about privileged access on systems that support fine-grained privileges.


munlockall() returns the following values:


Successful completion.


Failure. The requested operation is not performed. errno is set to indicate the error.


If munlockall() fails, errno is set to the following value:


The effective user ID of the calling process is not a user with the MLOCK privilege.


The following call to munlockall() unlocks the process virtual address space:



munlockall(): POSIX Realtime Extensions, IEEE Std 1003.1b

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