Compiling DROPS with GCC 4

Bjoern Doebel doebel at
Wed Jun 21 15:06:10 CEST 2006


>>>Is it possible to compile DROPS with GCC 4 now?
>>No, because there are some applications using Linux 2.4 sources (l4io,
>>dde_linux, ORe, ...), which in turn do not compile with GCC4.
> Do you have experience in linking libraries compiled with GCC 3.x with
> other code compiled with GCC 4? 

No, I'm sorry.

> Within EMSCB we try to move towards
> recent GCC versions and therefore currently encounter this problem.

DROPS only supports GCC major number 3 up to now. Many packets should
compile with GCC4, but those that use Linux kernel sources will not do
so until we switch everything to Linux 2.6.

> Do you have a list of packages not compatible with GCC 4 due to the
> above reasons? Probably we don't need these packages anyway.

The following packages in my local L4 tree reference the LINUX24_INCDIR
make variable:


> BTW: Why does l4io need Linux 2.4 sources? 

Because it accesses PCI hardware. (rest of explanation below)

> And: I thought you already moved to Linux 2.6 completely?

Note, that here is a difference between L4Linux and the use of Linux
sources in DROPS. L4Linux is always at the latest 2.6 kernel version and

To provide an easy way for direct hardware access from L4 servers and to
support a large amount of hardware, DROPS uses legacy Linux device
drivers. This is achieved by emulating a Linux driver environment
through dde_linux ( and
running the device drivers (nearly) unmodified within L4 servers.

dde_linux currently supports Linux 2.4 and moving it to 2.6 is on the
agenda, but I cannot tell you when this will be finished (the sooner the

So far
"If you put butter and salt on it, it tastes like salty butter."
-- Popcorn comes to the Discworld (Terry Pratchett, Moving Pictures)

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