plock.2 (2010 09)

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plock(2) plock(2)
NAME
plock() - lock process, text, data, stack, or shared library in memory
SYNOPSIS
#include <sys/lock.h>
int plock(int op);
DESCRIPTION
The plock() system call allows the calling process to lock the text segment of the process (text lock), its
data segment (data lock), or both its text and data segment (process lock) into memory. Stack segments
are also locked when data segments are locked. Shared library text and shared library data segments
(shlib lock) can also be locked. Locked segments are immune to all routine swapping.
plock() also
allows these segments to be unlocked.
The effective user ID of the calling process must be a user with the
MLOCK privilege.
op must be one of the following:
PROCLOCK Lock text and data segments into memory (process lock)
TXTLOCK Lock text segment into memory (text lock)
DATLOCK Lock data segment into memory (data lock)
UNLOCK Remove locks
SHLIBLOCK Lock shared library text and shared library data segments (shared library
lock)
PROCSHLIBLOCK Lock text, data and shared library text and shared library data segments into
memory (process and shared library lock)
TXTSHLIBLOCK Lock text, shared library text and shared library data segments into memory
(text and shared library lock)
DATSHLIBLOCK Lock data, shared library text and shared library data segments into memory
(data and shared library lock)
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.
RETURN VALUE
plock() returns the following values:
0 Successful completion.
-1 Failure. The requested operation is not performed. errno is set to indicate the error.
ERRORS
If
plock() fails, errno is set to one of the following values.
[EINVAL] op is equal to
PROCLOCK and a process lock, a text lock, or a data lock already
exists on the calling process.
[EINVAL] op is equal to
TXTLOCK and a text lock or process lock already exists on the calling
process.
[EINVAL] op is equal to
DATLOCK and a data lock, or process lock already exists on the cal-
ling process.
[EINVAL] op is equal to
UNLOCK and no type of lock exists on the calling process.
[EINVAL] op is equal to
SHLIBLOCK and there are no unlocked shared library segments in
the calling process.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1