I'm sure this question has been answered, apols in advance, but if you install Debian lenny and later get all the devel tools inside the build-essential, it's a good bet the gcc version will be different.

So you could end up "make" ing stuff with a gcc version different to your running kernel.

My question .. I take it, most people end up recompiling their kernel with the right resident gcc version? Do any more packages have to be recompiled after this? Like libc6 or something?

Personally i wouldn't be recompiling the kernel,you can install the appropriate gcc then temporarily use that version.
Here's an example:

You can check the version with:

Once you close the shell you will go back to running the original version of gcc.

environmental variables are one of my weaknesses.

I don't see $CC coming up too often, so, instead, I apt-get'd v4.1 and changed the /usr/bin/gcc symlink to point to it.

Thanks for the reply!

Hope you remembered to undo this change when you were done.

1) it does not matter if you use a different gcc version. All GCC versions for more than a decade are C standard compliant. What matters is that the development library (glibc) be the same version as the actual library in use, which if you install from packages it will be, and that the library in use is the one the kernel (and 100% of everything else) was compiled against. If that were not the case, you would probably find out right away and your system would be totally broken, but it seems very very unlikely IMO unless you do something incredibly stupid. Recompiling glibc itself is very difficult and you are about as likely to have done that by accident as you are to wake up on the moon tomorrow. So don't worry your head about it.

You don't even have to use GCC. You could try a different compiler; it's the devel libraries that count.

2) "Do any more packages have to be recompiled after this? Like libc6 or something?" For sure not, and as I just said you are unlikely to be able to do such a thing anyway.

Making your own kernel is fine -- I almost always replace the stock kernel. You can screw it up, but don't be scared away, just make sure you understand how to use grub to select a kernel so you can switch back to the original one (ie, make sure each one has it's own menu.lst entry).

There used to be a caveats, vis, which gcc version to use, but I have not seen one of those in years.

Anyway, just to reiterate: it does not matter about the gcc version. If they issued an updated gcc package tomorrow for some reason, it will be fine.

Also: the compiler used to build the distro kernel is probably *not* the distro compiler, no matter what -- but that's just a guess.