[En-Nut-Discussion] Nut/OS Initialization

[Nathan Moore]

On Wed, Sep 17, 2008 at 11:09 AM, Alain M. <alainm at pobox.com> wrote:

>
> Thiago A. Corrêa escreveu:
> > I don't know exactly how this is implemented in the C code, but we
> > could use this approach to remove the hardware init from main.
> > If some void hardwareInit() is provided, then it will be called before
> main (?)
>
> That is against C rules. So I vote against it :(


How is this against C rules?  Lots of stuff typically happens before main is
called in programs.
Under linux _init is the standard entry point for a program, and it loads
ld.so which is responsible
for loading any other libraries that the program needs before main is ever
called.  There is also a
test for static and/or global class constructor calls (even if the app isn't
C++, objective C, or other
OO language) that happens before main is called.
This isn't unlike the preparation that main() would need to come up.
Also, nut/os's main already does break the rules since it doesn't get argc
and argv and main can't
return in Nut/Os.
Having an user definable hardware init that gets called before threads are
enabled seems like a good
thing to me.  In other embedded OSes it's common for the first code that
runs to be code that wasn't
written by the OS vendor, but since Nut/Os is ~vended~ by the producer of
the boards that it is
intended to run on the current init is done by code that is in the OS
distribution.

Nathan