Отв.: Shared library link

Chris Johns chrisj at rtems.org
Mon Sep 26 08:23:12 UTC 2011

On 26/09/11 5:05 PM, Oleg Moroz wrote:
> Thanks for answer. Sorry for my english.

I understand. I will attempt to clearly state any assumptions on my part.

>  >What happens when the size of the code changes ?
> I'm developing my application with memory "segmentation". I mean:
> 0x40000000
> --------------
> main task
> --------------
> 0x40001000 (for example)
> -------------
> second task
> -------------
> 0x40002000
> -------------
> third task
> -------------
> 0x4000f000
> ------------
> functions like printf() and other common functions and data
> ------------
> 0x40001000-0x40000000 > sizeof(main task)
> 0x40002000-0x40001000 > sizeof(second task)
> ......
> I mean what i must manually locate all of this tasks in memory, and
> allocate memory "segment" for every task.

I did wonder if this was the approach. It does still seem a little fragile.

> It will be doing by main task
> that could load task code from EEPROM. I'm trying to create mechanism to
> dynamicallyloading and unloading tasks like it did in usual OSes with
> processes.

Is this to occur without RTEMS restarting ?

Where is the code to manage this located and what happens with the heap.

> This mechanism need not be universally. It only for this
> project now.


>>I suggest you take a look at:
> Thanks. Now i'm downloading archive from this directory, and will see
> what is it.

Please remember there is another package which is a host linker to be 
uploaded. It is a C++ application with classes to manage some of what I 
suspect you are attempting to do. It is a work in progress and I wish to 
change some parts.

>>In the traditional definition dynamic and static libraries are not the
> same type of code. They can varying depending on the specific method
> used by the operating system. As Joel stated RTEMS is a single address
> space or processes and will not support the Unix
>>(ELF) shared library model. It adds overhead for no gain. Given this I
> am not sure I understand your sentence. For example have you built
> shared RTEMS libraries (the tools will let you do this) and static
> libraries and are you attempting to mix the results ?
> I will try.

I would not. Any shared code with RTEMS requires -PIC code as per Linux.


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