plock(2) — System Calls
NAME
plock − Lock the text and/or data segments of a process in memory
SYNOPSIS
#include <sys/lock.h>
int plock(
int opr );
PARAMETERS
oprSpecifies one of the following operations:
PROCLOCK
Locks the text and data segments into memory.
TXTLOCK
Locks the text segment into memory.
DATLOCK
Locks the data segment into memory.
UNLOCK
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. Memory 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:
[EAGAIN]
There are insufficient resources to perform the operation.
[EINVAL]
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.
[EPERM]
The caller does not have appropriate privilege.