[lel]

Is there any reason for using flex version 2.4.5
and not some modern version of flex installed in the system anyway?

I tried to use system flex (2.5.31). It compiles without problem.

To do that it is necessary eliminate shipped
FlexLexer.h from lnInclude which is not obvious thing.

[lel]

Sorry, I was not right.

flex++ installed in in my system (ubuntu-6.06)
cannot compile all .L files in OpemFOAM.
More precise - output from flex++ cannot be compiled by g++

There are two types of error messages:
- duplicate class definition
- absence of 'main' on link stage

However it is still interresting what is so special in OpenFOAM that it cannot use standard flex++ and should use patched version of it?

[hjasak]

Easy: standard flex does not conform with the C++ standard and the new compilers refuse to work with it. Also, I got annoyed with the warnings about using non-standard headers etc and this got fixed as well.

Note that flex needs to produce a proper code for later compilation, so adherence to standard is really important. At the same time (the last time I've looked), nobody is giving flex the attention it needs.

(if you want something done properly, you end up doing it yourself) :-)
Hrv