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 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 fails and does 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. 

­[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. 

­[EAGAIN] Not enough memory. 

SEE ALSO

exec(2), exit(2), fork(2). 

DIAGNOSTICS

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. 

September 02, 1992