Hi,

If I understand correctly, this is the same type of idea of the linux kernel's __init magic, except that no code cleanup is done?

Regards
Sebastien

On Fri, Jun 25, 2010 at 3:28 AM, Harald Welte <laforge@gnumonks.org> wrote:
Hi!

As indicated in other mails, we now have support for gcc-style constructors
in OsmocomBB.  The way to use them is relatively easy:  Simply put
"__attribute__((constructor))" at the function that you want to be
called during initialization.

The way how this works is like this:
* gcc and the linker create a table of function pointers to all the
 functions with that attribute
* the code in compal_ramload_start.S takes care of calling
 lib/ctors.s:do_global_ctors() which iterates over the list
 and calls each constructor

This concept is now used for things like prim_fbsb_init() in layer1,
but I have also started to use it for board_init().  This means that
board_init() no longer needs to be called from the main() function
of each app.

We can probably put more stuff into constructors, but we should also
be careful as with gcc-4.0.2 we cannot yet indicate priorities and thus
there is no explicit way to control the ordering in case of dependencies.

Regards,
       Harald
--
- Harald Welte <laforge@gnumonks.org>           http://laforge.gnumonks.org/
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