Problem: shared object loading runs constructor of a static object, but static linkage does not.

[tropos]

(Platform: Solaris with gmake and native Sun C++ compiler)

Problem: If I create a shared object (.so file) and load it into a
executable, the loader correctly runs constructors of static objects in
the .so file. But if I link the same code statically, with no shared
object, then the constructors don't run at all! Why??

Here's an example:

<file AnnounceConstru ction.cpp>

#include <iostream> //for cout
#include <ostream> //needed for cout linkage

class AnnounceConstru ction
{
public:
AnnounceConstru ction()
{ std::cout << "AnnounceConstr uction constructed."
<< std::endl; }
};

//The static object
AnnounceConstru ction _static_Announc eConstruction_i nstance;

<file main.cpp>
#include <iostream> //for cout
#include <ostream> //needed for cout linkage

int main()
{
std::cout << "main() has run." << std::endl;
}

# Now I compile AnnounceConstru ction.cpp into an archive, link
statically,
# and show that the constructor of AnnounceConstru ction does not run.

staticdynamic> CC -c AnnounceConstru ction.cpp -o
obj/AnnounceConstru ction.o
staticdynamic> CC -xar -o AnnounceConstru ction.a
obj/AnnounceConstru ction.o
staticdynamic> CC main.cpp -Bstatic AnnounceConstru ction.a -o test.out
staticdynamic> ./test.out
main() has run.
staticdynamic>

# This time, I compile AnnounceConstru ction.cpp into a shared object,
link,
# and show that the constructor runs correctly.
staticdynamic> CC -G obj/AnnounceConstru ction.o -o
AnnounceConstru ction.so
staticdynamic> CC main.cpp -L. -Bdynamic AnnounceConstru ction.so -o
test.out
staticdynamic> export LD_LIBRARY_PATH =.:$LD_LIBRARY_ PATH
staticdynamic> ./test.out
AnnounceConstru ction constructed.
main() has run.
staticdynamic>

Can anyone explain this?

[Howard]

"tropos" <tr**********@h otmail.com> wrote in message
news:11******** **************@ g47g2000cwa.goo glegroups.com.. .

(Platform: Solaris with gmake and native Sun C++ compiler)

Problem: If I create a shared object (.so file) and load it into a
executable, the loader correctly runs constructors of static objects in
the .so file. But if I link the same code statically, with no shared
object, then the constructors don't run at all! Why??

Linking and loading are not issues covered by the C++ language standard, and
thus are off-topic here. You need to ask in a newsgroup devoted to your
platform.
-Howard

[GB]

tropos wrote:

(Platform: Solaris with gmake and native Sun C++ compiler)

Problem: If I create a shared object (.so file) and load it into a
executable, the loader correctly runs constructors of static objects in
the .so file. But if I link the same code statically, with no shared
object, then the constructors don't run at all! Why??

Here's an example:
staticdynamic> CC -c AnnounceConstru ction.cpp -o
obj/AnnounceConstru ction.o
staticdynamic> CC -xar -o AnnounceConstru ction.a
obj/AnnounceConstru ction.o
staticdynamic> CC main.cpp -Bstatic AnnounceConstru ction.a -o test.out
staticdynamic> ./test.out
main() has run.
staticdynamic>

Your AnnnounceConstr uction.o file is not actually getting pulled in from
the .a file because main.o has no dependencies on it. That's the whole
point of ar files. You only get what you use. Try compiling by explicity
listing the .o file on the CC line instead of creating an ar file.

Gregg

[None]

Another option to solve your problem is to pass some command line args
to the linker to tell it not to be so smart about deciding which
symbols to import or not. This varies tremendously by platform - for
example, using gnu ld, you would use the option --whole-archive (I
think - it's been a while since I've done this. The man page gives a
good explanation of how to use it.

-matt