PLOCK(S) UNIX System V PLOCK(S)
Name
plock - lock process, text, or data in memory
Syntax
#include <sys/lock.h>
int plock (op)
int op;
Description
The plock system call 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
The plock system call will fail and not perform the
requested operation if one or more of the following is 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(S), exit(S), fork(S)
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.
Standards Conformance
plock is conformant with:
AT&T SVID Issue 2, Select Code 307-127;
and The X/Open Portability Guide II of January 1987.
(printed 6/20/89)