NAME

plock − lock process, text, or data in memory

SYNOPSIS

#include <sys/lock.h>

int plock (op)
int op;

DESCRIPTION

Plock 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.  Locked segments are immune to all routine swapping.  Plock also allows these segments to be unlocked.  To use this call, the calling process must be a member of a privilege group allowing plock (see setprivgrp on getprivgrp(2)) or the effective user ID of the calling process must be super-user. 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

EXAMPLES

The following call to plock locks the calling process in memory:

plock (PROCLOCK);

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. 

ERRORS

Plock will fail and not perform the requested operation if one or more of the following are true:

­[EPERM] The effective user ID of the calling process is not super-user and the user does not have PRIV_MLOCK. 

­[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 a process lock already exists on the calling process. 

­[EINVAL] 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. 

­[EINVAL] Op is not equal to either PROCLOCK, TXTLOCK, DATLOCK, or UNLOCK. 

­[EINVAL] Plock not allowed in [vfork, exec] window (see vfork(2)).

SEE ALSO

exec(2), exit(2), fork(2). 

Hewlett-Packard Company  —  Version B.1,  May 11, 2021