plock(2)plock(2)NAMEplock - Lock the text and/or data segments of a process in memory
SYNOPSIS
#include <sys/lock.h>
int plock(
int opr );
PARAMETERS
Specifies one of the following operations: Locks the text and data seg‐
ments into memory. Locks the text segment into memory. Locks the data
segment into memory. Removes locks.
DESCRIPTION
The plock() function locks or unlocks a process's text segments, data
segments, or both in physical memory. When locked, the physical pages
containing the text or data segment will not be paged out. It is an
error to lock a segment that is already locked.
The caller must have superuser privilege to use the plock() function.
Note that memory acquired subsequent to a plock() call may or may not
be locked in memory, depending on the specific acquisition method. Mem‐
ory acquired by using the brk() or sbrk() function will be locked if
the data segment was locked. Memory acquired by means of the mmap() or
vm_allocate() function will not be locked.
RETURN VALUES
Upon successful completion, a value of 0 (zero) is returned to the
calling process. Otherwise, a value of -1 is returned and errno is set
to indicate the error.
ERRORS
If the plock() function fails, errno may be set to one of the following
values: There are insufficient resources to perform the operation. One
of the following occurred: The opr parameter is PROCLOCK, but the text
segment or the data segment is already locked. The opr parameter is
TXTLOCK, but the text segment is already locked. The opr parameter is
DATLOCK, but the data segment is already locked. The opr parameter is
UNLOCK, but neither the text segment nor the data segment is locked.
The caller does not have appropriate privilege.
SEE ALSO
Functions: brk(2), mmap(2)plock(2)
