AT&T UNIX™PC Unix System V Users Manual - tenox

PLOCK(2) PLOCK(2)
NAME
plock - lock process, text, or data in memory
SYNOPSIS
#include
int plock (op)
int op;
DESCRIPTION
Plock allows the calling process to lock its text segment (text
lock), its data segment (data lock), or both its text and data segments
(process lock) into memory. 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
super-user to use this call. Op specifies 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
Plock will fail and not perform the requested operation if one or
more of the following are true:
The effective user ID of the calling process is not superuser.
[EPERM[
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 a process
lock already exists on the calling process. [EINV AL]
Op is equal to DATLOCK and a data lock, or a process
lock already exists on the calling process. [EINVAL]
Op is equal to UNLOCK and no type of lock exists on the
calling process. [EINV AL]
RETURN VALUE
Upon successful completion, a value of 0 is returned to the calling
process. Otherwise, a value of -1 is returned and errno is set to
indicate the error.
SEE ALSO
exec(2), exit(2), fork(2).
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