Dynamic load real-time tasks

Павел Жданов paul.alex.zhdanov at gmail.com
Mon Jun 26 08:34:46 UTC 2017

Hello everyone.

I'm interested in dynamic loading and have the following situation:

   1. There are two files init.c and dl.c.
   2. dl.с defines rtems_main function . This function just print some
   string using printf fuction. It complied to dl.o but not linked against
   standard libraries so printf symbol is unresolved.
   3. I want to load dl.o from init.с and use rtems_main function (with
   dl_open and so on). Final init.exe is linked against standard libraries so
   it has printf symbol resolved.
   4. dl.o is loaded from the dos partition.
   5. At the moment a can load dl.o and call rtems_main only if it doesn't
   use printf or functions from other libraries.

My questions are:

   1. Is this scenario possible?
   2. How to link dl.o with init.exe to resolve printf (and may be other
   functions that are used by rtems_main and resolved in init.exe)?

Platfrom: i386, pc486. I tried to use rtems-ld and i386-rtems4.11-ld but
could not resolve necessary symbols.

Best regards,
Pavel Zhdanov.

С уважением, Жданов Павел.

On Wed, May 3, 2017 at 1:24 PM, Павел Жданов <paul.alex.zhdanov at gmail.com>

> Hi.
> Really, is it possible to load tasks dynamically in runtime? I'm
> interested in software updating. So far I think that final executable file
> in RTEMS is monolithic image. It's big and it's take a lot of time to
> upload it via serial port. If it's not modular then I can't upload new task
> and start it. Can you suggest some methods that can be used to update RTEMS
> task at runtime? For example update some of its functions using the dynamic
> linker (dlopen, ...).
> Best regards,
> Pavel Zhdanov
> С уважением, Жданов Павел.
> On Wed, Apr 5, 2017 at 10:22 AM, xuelin.tian at qkmtech.com <
> xuelin.tian at qkmtech.com> wrote:
>> Dear all,
>> Can I load real-time tasks using real-time loader?
>> In my opinion, loading real-time tasks means that I can append my own
>> application tasks to the interrupt ISR, and this task can be invoked based
>> on a predefined frequency.
>> In VxWorks, I need to disable interrupt first, using sysAuxClkDisable,
>> and enable this interrupt after install my application tasks.
>> Do we have the same mechanism in RTEMS?
>> ------------------------------
>> Best wishes,
>> xuelin.tian at qkmtech.com
>> _______________________________________________
>> users mailing list
>> users at rtems.org
>> http://lists.rtems.org/mailman/listinfo/users
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