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Wireshark-dev: Re: [Wireshark-dev] Windows build for VS 2008

From: Nathan Jennings <njen@xxxxxxxxxxxx>
Date: Mon, 28 Jul 2008 14:49:01 -0400
Thanks for the feedback...

One thing I forgot to mention/ask is if the SVN Makefile.nmake set the "_DEBUG" (or "DEBUG", whatever is correct) macro for Wireshark builds so the default build is a debug version?

If so, on VS 2008 Pro, my VS version, the compile flag for "Runtime Library" (specifies runtime library for linking) is "/MDd" (Multi-threaded Debug DLL) for a debug build, not "/MD" (Multi-threaded DLL).

I remember looking at Makefile.nmake and seeing the option "/MD" being passed somewhere.

Just thought I'd mention this in case there is a discrepancy between VS 2005 and 2008, or other versions.

Thanks again, -Nathan


On 7/28/2008 5:38 AM, Graham Bloice wrote:
Nathan Jennings wrote:
On 7/25/2008 11:50 AM, Graham Bloice wrote:
Gerald Combs wrote:
According to
http://kobyk.wordpress.com/2007/07/20/dynamically-linking-with-msvcrtdll-using-visual-c-2005/ it's possible to use newer versions of Visual C++ to link against the "classic" msvcrt.dll instead of msvcr[789]?.dll. This might let us get rid of some of the complexity in the current Windows build environment and let us use a newer
compiler for the official builds.
_______________________________________________

Hmm. The article seems to imply some other complexity as the debug CRT isn't available so you have to use the one for your compiler toolchain when debugging. In addition, AFAIK, our CRT problems come from using compiled binaries from other projects (adns, etc.) that *currently* use the VS 6 CRT but may switch at any time. I think we'd still have to ensure all components we use are running with the same CRT thus the hassles with having to compile them with the CRT of the developers toolchain.


Thanks for the link to the bug id.

So how does it work now? I mean tracking the CRT for other projects Wireshark calls into/depends on?
Manually, by fiddling the makefiles and ensuring that the dlls get rebuilt with the users current toolchain (and crt) for the problematic cases.
I'm guessing the big ones are GTK/Glib and WinPcap? So do they use MSVC 2005 EE or, at least, the same CRT?
The problem ones are adns and zlib. GTK relies on Glib and Glib doesn't import any specific CRT. Using depends (http://www.dependencywalker.com/) can help you identify the linkages.
If I'm reading/understanding Gerald's link to the post and Graham's message correctly, then you can link/import to any CRT you'd like regardless of compiler version (i.e. use CRT v8 with VS 2008 or CRT v7 with VS2005)?
I'm not sure about that. The article seems to be talking about getting around the issue of linking to a specific CRT that isn't installed on the target machine. By using the tricks described, it would seem that an app can be made to use whatever CRT is available. I don't think it gets around the issue of different components of an app using different versions of CRT, but I'm assuming Gerald's thinking was that we could make wireshark itself link to the VC 6 CRT on all toolchains, and hence have no issues with the third part dll's that also do that.
What I'm getting at is Wireshark could potentially call into three different CRTs if there were two other binary projects and they were compiled to two different CRT versions, correct?

I.e. Wireshark CRTv8, GTK/Glib CRTv7, WinPcap MSVCRT.

I don't think you can do that within the same app.


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