Category: Software

Today I’m starting something new on this blog. Whenever I find a solution to a software development problem I encounter and believe it’s worth telling, I’ll write it here.

This time – loading different shared libraries when analyzing a core dump in GDB on Linux. By “different” I mean “not the libraries that GDB finds and uses when the core dump is loaded”. The motivation to do this is, for example, if you have libraries on the computer you’re using to analyze the core dump that are different from the libraries which were used while the application ran. If you have the latter in some directory, say in the path /tmp/core/libs, then the way to redirect GDB to them is:

(gdb) set solib-absolute-prefix /dev/null/
(gdb) nosharedlibrary
(gdb) set solib-search-path /tmp/core/libs

Note that /tmp/core/libs must be a full path, without using ~ or anything. It doesn’t work. My guess is that this is unacceptable by the loader, which loads the libraries starting from the specified path.

Not too long ago I installed Microsoft’s Visual C++ Express Edition 2005 (link to all express editions of Visual Studio) at home. Mainly because I needed a good development environment for C++, and not for developing something big. Visual Studio 2005 has a solid feel to it, unlike Visual Studio .NET 2003, which always gave you a sense of insecurity in the sense that it might crash on the next mouse click event (and definitely unlike Visual Studio .NET 2002, which actually did crash).

Another good thing about Visual C++ Express Edition 2005 is that you can open a new project from existing code and still get the benefits of IntelliSense, which has also improved. I use this feature to edit work-related code at home instead of remote-controlling my work PC from home. I didn’t try writing Windows code, only native C++ code (and I definitely didn’t try writing managed C++ code).

So, generally speaking, my first impression is very good. I like Visual C++ Express Edition 2005. It’s a solid product, and best of all – it’s completely free (as in beer). However, I have two complaints:

1. To write a native C++ application you have to start from an empty project. Otherwise, Visual Studio will write a function called _tmain() instead of main() for you. There’s probably a reason for this, but if you’re a student who just wants to write plain C code for a course, it’s an annoyance.
2. The default debug settings for an empty project cannot be used for debugging. This is very strange and very annoying. Why is it called a debug build if I can’t actually, you know… debug? Anyway, the settings you need to change in order to debug are in your project’s properties:
   • C/C++ -> General: Debug Information Format=Program Database
   • C/C++ -> Optimization: Optimization=Disabled
   • Linker -> Debugging: Generate Debug Info=Yes