linking C++/D static library - what is "crt0.o"?

[Daniel Murphy via digitalmars-d-ldc]

"bitwise"  wrote in message news:ckjqktzsmonjdcrhkhfg at forum.dlang.org...

> However, when I try to make a static library with the above files, it 
> fails:
>
> > ldc2 -c -od/.../test_lib/obj/Debug main.d
> > clang++ -c -working-directory /.../test_lib/obj/Debug ../../native.cpp
> > clang++ -static -working-directory /.../test_lib 
> > /.../test_lib/obj/Debug/main.o 
> > /.../test_lib/obj/Debug/native.o -obin/Debug/libtest_lib.a

IIRC passing -static to gcc/clang means 'statically link with C runtime 
libraries' not 'make a static library'.  To create a static lib you need to 
create object files with -c and use 'ar' to create the static library.

http://www.adp-gmbh.ch/cpp/gcc/create_lib.html

> > ld: library not found for -lcrt0.o
> > clang: error: linker command failed with exit code 1 (use -v to see 
> > invocation)
>
> So what is "-lcrt0.o" and why is clang trying to automatically add it to 
> my static library?

crt0.o contains the code to call C's main and a few other things.  It is 
automatically added when building an executable.  The error possibly means 
your system isn't set up for statically linking the cruntime.