HP-UX Reference (11i v1 00/12) - 3 Library Functions A-M (vol 6)

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datalock(3C) datalock(3C)

NAME

datalock() - lock process into memory after allocating data and stack space

SYNOPSIS

#include <sys/lock.h>

int datalock(size_t datsiz, size_t stsiz);

DESCRIPTION

datalock() allocates at least datsiz bytes of data space and stsiz bytes of stack space, then locks the

program in memory. The data space is allocated by malloc() (see malloc(3C)). After the program is

locked, this space is released by free() (see malloc(3C)), making it available for use. This allows the cal-

ling program to use that much space dynamically without receiving the SIGSEGV signal.

The effective user ID of the calling process must be super-user or be a member of or have an effective group

ID of a group having PRIV_MLOCK access to use this call (see setprivgrp(2)).

EXAMPLES

The following call to datalock() allocates 4096 bytes of data space and 2048 bytes of stack space, then

locks the process in memory:

datalock (4096, 2048);

APPLICATION USAGE

datalock() is thread-safe. It is not async-cancel-safe.

RETURN VALUE

datalock() returns -1 if malloc() cannot allocate enough memory or if plock() returned an error

(see plock(2)).

WARNINGS

Multiple datalocks cannot be the same as one big one.

Methods for calculating the required size are not yet well developed.

AUTHOR

datalock() was developed by HP.