kDtaAccs.Kernel Data Access

Product : ISaGRAF 3.x

Date : 17-April-1998

File : kDtaAccs.Kernel Data Access.htm

Subject : Kernel Data Access

Keywords: Kernel access - Server - Space 2

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The official product which allow access to the kernel application

data access is the SERVER product (package included in the IDK)

Generally speaking this tool allow:

1) Symbols management

2) Kernel application data access within linked edited user

function (usually through hooks)

3) Any user task (on multitasking systems of course)

to access to the kernel application data (Read/Write) through

provided library services. The access is Request/Answer based

on through shared memory and semaphores.

NT target Specific note:

The server product is not available with NT target.

The official way to access kernel application data is using DDE

or OPC.

More than that, some people wish to directly access the

application data.

THIS IS NOT RECOMMENDED.

THE FOLLOWING INFORMATION IS NOT PART OF PUBLIC INTERFACES. THEY

ARE NOT SUPPORTED AND ARE SUBJECT TO CHANGES WITHOUT ANY

NOTIFICATION

Obviously the kernel application data are stored in shared memory

space number 2. It starts with a header which structure is defined

in tasy0ker.h file as str_ker. This header mainly contains pointer

to different types of data (Booleans, analogs,...).

The content of this space is mainly described through take0ini.c

file at space construction.

Therefore any user task can still link the space to proceed data.

BUT take care of memory mapping constraints, non coherent

cycle data image, ....

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