Re: problem with static member variable in dynamic library

[matze <matze at indymedia dot org>]

answering my own question:

it's the -nostartfiles option thats causing the problem:

<snip>

This is because the code that calles global constructors is located in
the default _init(). So, when you start a C++ program normally linked,
first code from _init() calls all global constructors, and then main()
is called, so in main() you have all global objects already
constructed
properly.

If you don't execute the default _init(), global constructors are not
called.

</snip>

http://www.mail-archive.com/linux-development-apps@senator-bedfellow.mit.edu/msg00514.html

now i have to figure out who set this option and why ;)

matze

El Tue, Mar 29, 2005 at 01:56:47PM +0200 matze ha dit:

> hi,
> 
> i'm having a problems with the use of static member variables inside
> a dynamic library.
> 
> an example of the problem:
> 
> class OtherClass
> {
> 	// ...
> };
> 
> class ThisClass
> {
> 	private:
> 		static OtherClass ok;
> 		static int alsoOk;
> 		static std::string error;
> };
> 
> (the static members are instantiated in the .cpp file)
> 
> the code compiles and links, the problem arises when loading the
> dynamic library: it's ok to have library interal classes (like
> OtherClass) or basic types (like the int) as static members but when
> using 'external' classes like std::string or others, the loading of
> the library fails. the utility dltest reports the error "undefined
> symbol: __dso_handle".
> 
> the system is an amd athlon 1 GHz, running Fedora Core 2, with g++
> version 3.3.3. the compiler options are "-W -Wall -pthread -march=i586
> -ggdb". linking is done with "ld -nostartfiles -shared -o libfoo.so
> <objects> -lpthread <project libs>"
> 
> thanks in advance
> 
> matze
> 



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