How and when is static linking performed (MinGW)?

I had a lot of pain linking a C++ application to another C++ library with Fortran90 dependencies (MinGW, TDM g++ and gfortran). I either have to use gfortran for linking 开发者_开发问答or the application crashes on startup (in global constructors keyed to __cxa_get_globals_fast). However this is not acceptable, I would like to use g++ for linking (Qt GUI).

It seems to me that the dependencies of the libraries cannot be linked statically with gcc, linking is only performed when main() is available. Why?

I guess partly because code for certain initializations have to be inserted before main().

Why is it that the statically linked application needs DLL-s, such as mingwm10.dll or pthreadGCE2.dll at runtime? Why can't these be statically linked?

UPDATE: I just found these websites:

http://www.deer-run.com/~hal/sol-static.txt

http://www.iecc.com/linker/

The main difference between linking with gfortran and using ld/gcc/g++ to link is that gfortran links the standard fortran libraries by default, whereas with another linker you will need to manually specify the libraries to link. I wasn't able to find them with a quick search, but it should be along the lines of -lgfortran.

Also, gfortran has some specific instructions for initialisation routines that need to be called for certain fortran intrinsics to work if your main program is not written in fortran. If you haven't called these routines then this might cause a crash.

Why is it that the statically linked application needs DLL-s, such as mingwm10.dll or pthreadGCE2.dll at runtime? Why can't these be statically linked?

They can, but static library versions are not provided due to the fundamental advantage of dynamic libraries: bugs can be fixed without rebuilding the executables.