Re: Exporting debugging symbols in a static .lib

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 3 Nov 2009 08:18:05 -0800 (PST)
Message-ID:
<8b04c341-f231-4886-ad68-11f052e67506@a31g2000yqn.googlegroups.com>
On Nov 3, 3:50 pm, "Alex Blekhman" <tkfx.NOS...@yahoo.com> wrote:

"James Kanze" wrote:

It is no different from .EXE or .DLL file. You supply the
resulting .PDB file along with the project output.


Which causes what commands to be generated? I'm building
from the command line.


For .EXE or .DLL file you run linker tool with /PDB command,
which generates resulting .PDB file. Also, linker embeds
reference to this .PDB file into the executable.

However, static library is built without linker. So, we have
/Zi (or /ZI) and /Fd compiler options to generate .PDB file. I
have never tested it personally, but it seems that compiler
merges debug information if the same .PDB filename is
specified for several source files.

Does this mean that if I compile the different objects with
the same program database file, they'll merge, rather than
the last one overwriting the previous one?


Yes, it seems to be the case. I have static library project
with default .PDB filename ("VC90.pdb") for all source files.
Nonetheless, during debug session the information is available
for every symbol, no matter from which source file it came
from.


A little bit of experimentation here seems to show the same
thing.

If you don't specify /Fd option (either via project
settings or manually), then the .PDB file name defaults to
VCx0.pdb., where x is the major version of Visual C++ in
use.


That may be a good solution for me; I can later rename or
copy the file when building the library.


I am afraid this setup won't work smoothly. The problem is
that compiler embeds full path of the .PDB file into .OBJ
file. So, if you rename original .PDB file, then you'll get
into troubles during debug session.


Ouch. That means that even copying the debug information for
each individual file won't work.

I think the best solution in your case is to specify /Z7
compiler option. It will cause the compiler to generate debug
info directly into .OBJ files leaving out .PDB hustle
altogether.


Yes. But is the debug information as complete? (And if so, why
doesn't Microsoft use it as the default, or even exclusively?)

I'll give it a try, anyway.

--
James Kanze

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