[Cmake] File and compiler specific flags?

[Sebastien BARRE]

Hi Bill, Amitha

Amitha, I would just like to add that you can also check the value of 
CMAKE_CXX_COMPILER and matches it against a specific compiler. For example 
(here for the Visual C++ 6.0, i.e. VC++60) :

IF (VTK_USE_ANSI_STDLIB)
   IF (CMAKE_CXX_COMPILER MATCHES "^VC\\+\\+60$")
     SET (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /D \"NOMINMAX\"")
   ENDIF (CMAKE_CXX_COMPILER MATCHES "^VC++60$")
ENDIF (VTK_USE_ANSI_STDLIB)

Furthermore :

At 17/08/2001 17:57, Bill Hoffman wrote:
>You guessed it:
>
>IF(CMAKE_COMPILER_IS_GNUCXX)
>         SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ftemplate-depth-50")
>ENDIF(CMAKE_COMPILER_IS_GNUCXX)

I's working, but there is a slight problem anyway : the new CMAKE_CXX_FLAGS 
value does not make its way to the cache, although the original value has 
the following syntax (here, for Windows) :

SET (CMAKE_CXX_FLAGS "/W3 /Zm1000 /GX /GR" CACHE STRING
         "Flags used by the compiler during all build types, /GX /GR are 
for exceptions and rtti in VC++, /Zm1000 increases the compiler's memory 
allocation to support ANSI C++/stdlib")

I guess we talked about that already privately Bill (and the fact that 
there is no SET (VAR value CACHE TYPE) syntax) , but what is worrying me is 
that even the SET (VAR value CACHE TYPE "doc string") syntax won't fix the 
problem :

>IF(CMAKE_COMPILER_IS_GNUCXX)
>         SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ftemplate-depth-50" 
> CACHE STRING "new comment")
>ENDIF(CMAKE_COMPILER_IS_GNUCXX)

=> nothing is written to the cache
=> CMAKE_CXX_FLAGS is *not* changed, even internally (try with some bogus 
option to make it crash : it won't).