RE: dynamic libraries: custom _init() without losing default _init()

RE: dynamic libraries: custom _init() without losing default _init()

[Zagorodnev, Grigory]

Hi, Matze!
I'm actually surprised that preinit_array disallowed for DSO. 

Thus you may try to use ".init_array" section in the same manner. That
works fine for DSO but makes your initialization routine called _after_
C++ file-scope object constructors. Does the order really matter?

- Grigory

>-----Original Message-----
>From: matze [mailto:matze@indymedia.org]
>Sent: Wednesday, March 30, 2005 2:34 AM
>To: Zagorodnev, Grigory
>Cc: gcc-help@gnu.org
>Subject: Re: dynamic libraries: custom _init() without losing default
>_init()
>
>El Wed, Mar 30, 2005 at 01:05:26AM +0400 Zagorodnev, Grigory ha dit:
>
>> >to initialize the dynamic library a custom _init() is called. is it
>> >possible to call default _init() from the custom one or is there
>> >another way to invoke a custom function from default _init() or
>> >directly afterwards?
>>
>> It would be safer to not override default startup code, but use one
of
>> the following:
>>
>> Once your code is C++ you can create file-scope instance of some
>> initialization class so its constructor will do the work. This is
most
>> portable approach.
>>
>> In case library initialization code must be executed _before_ any C++
>> object constructor, you may use ".preinit_array"
>> 	static preinit(int argc, char *argv[]);
>> 	static void (*const preinit_ptr) (int argc, char *argv[])
>> 	     __attribute__ ((section (".preinit_array"))) = &preinit;
>
>thanks for your answer grigory, if that works it's actually cook :)
>
>i tried it, but the linker complains about the following:
>
>matze@assata:/tmp$ g++ -shared foo.cpp -o foo.so
>/usr/bin/ld: /tmp/cc1zrrRc.o: .preinit_array section is not allowed in
>DSO
>
>any idea?
>
>matze
>
>--
>             You must have a plan. If you don't have a plan,
>               you'll become part of somebody else's plan
>
>    ( ( ( i ) ) )  http://barcelona.indymedia.org  ( ( ( i ) ) )
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>                                                                `. `'`
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Re: dynamic libraries: custom _init() without losing default _init()

[matze]

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El Wed, Mar 30, 2005 at 10:24:46AM +0400 Zagorodnev, Grigory ha dit:

> I'm actually surprised that preinit_array disallowed for DSO. 
> 
> Thus you may try to use ".init_array" section in the same manner. That
> works fine for DSO but makes your initialization routine called _after_
> C++ file-scope object constructors. Does the order really matter?

with ".init_array" it works and fits perfectly our needs

thanks a lot!

matze

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Re: dynamic libraries: custom _init() without losing default _init()

[matze]

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El Wed, Mar 30, 2005 at 01:05:26AM +0400 Zagorodnev, Grigory ha dit:

> >to initialize the dynamic library a custom _init() is called. is it
> >possible to call default _init() from the custom one or is there
> >another way to invoke a custom function from default _init() or
> >directly afterwards?
> 
> It would be safer to not override default startup code, but use one of
> the following:
> 
> Once your code is C++ you can create file-scope instance of some
> initialization class so its constructor will do the work. This is most
> portable approach.
> 
> In case library initialization code must be executed _before_ any C++
> object constructor, you may use ".preinit_array"
> 	static preinit(int argc, char *argv[]);
> 	static void (*const preinit_ptr) (int argc, char *argv[])
> 	     __attribute__ ((section (".preinit_array"))) = &preinit;

thanks for your answer grigory, if that works it's actually cook :)

i tried it, but the linker complains about the following:

matze@assata:/tmp$ g++ -shared foo.cpp -o foo.so
/usr/bin/ld: /tmp/cc1zrrRc.o: .preinit_array section is not allowed in
DSO

any idea?

matze

-- 
             You must have a plan. If you don't have a plan,
               you'll become part of somebody else's plan

    ( ( ( i ) ) )  http://barcelona.indymedia.org  ( ( ( i ) ) )
                                                                 .''`.
    using free software / Debian GNU/Linux | http://debian.org  : :'  :
                                                                `. `'`
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RE: dynamic libraries: custom _init() without losing default _init()

[Zagorodnev, Grigory]

>to initialize the dynamic library a custom _init() is called. is it
>possible to call default _init() from the custom one or is there
>another way to invoke a custom function from default _init() or
>directly afterwards?
>
>matze

It would be safer to not override default startup code, but use one of
the following:

Once your code is C++ you can create file-scope instance of some
initialization class so its constructor will do the work. This is most
portable approach.

In case library initialization code must be executed _before_ any C++
object constructor, you may use ".preinit_array"
	static preinit(int argc, char *argv[]);
	static void (*const preinit_ptr) (int argc, char *argv[])
	     __attribute__ ((section (".preinit_array"))) = &preinit;

- Grigory

dynamic libraries: custom _init() without losing default _init()

[matze]

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hi,

now i understand why i had/have problems with statical member
variables (http://gcc.gnu.org/ml/gcc-help/2005-03/msg00270.html) a new
question arises:

to initialize the dynamic library a custom _init() is called. is it
possible to call default _init() from the custom one or is there
another way to invoke a custom function from default _init() or
directly afterwards?

ciao

matze

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