[CMake] wrapper around real compiler

[Jakub Zakrzewski]

Hi.
What scl enable devtoolset-2 does, is basically change the environment for the command. I use one of two techniques to make it working. When doing manual builds, I simply:
scl enable devtoolset-2 bash
And do everything from the new shell. On our CI, I put the following in build script (before calling cmake):
. /opt/rh/devtoolset-2/enable
As there is no magic but only environment variables involved, you can probably set them all using -DCMAKE_... options. Just look at the script and set, what you need. 
Remember, that devtoolset-2 is really just GNU Toolset in 4.8 version installed in non-standard location.

--
Gruesse,
Jakub





From: CMake [mailto:cmake-bounces at cmake.org] On Behalf Of Tomasz Majchrowski
Sent: Dienstag, 11. März 2014 19:44
To: cmake at cmake.org
Subject: [CMake] wrapper around real compiler

Dear All, 
I found cmake provides many techniques to integrate tools like distcc, ccache into the build system. In particular variables like the following could be used:

-D CMAKE_C_COMPILER="ccache" -D CMAKE_C_COMPILER_ARG1="gcc"
The picture becomes more complicated when the tools around the real compiler requires "special" syntax. As an example the RedHat's scl is such a one as it's requires quotation of the complete compiler line:

 scl enable devtoolset-2 'g++ -o output_file source_file...'
Details: https://access.redhat.com/site/documentation/en-US/Red_Hat_Developer_Toolset/2/html/User_Guide/sect-GCC-CPP.html

I was playing with build rules, however didn't success on try_compile which seems to ignore them.

set ( CMAKE_C_COMPILE_OBJECT    "<CMAKE_C_COMPILER> enable devtoolset-2 ' gcc <DEFINES> <FLAGS> -frandom-seed=<SOURCE>/ -o <OBJECT> -c <SOURCE>' ")
The only working one that I found is to use small bash script which will act as yet another wrapper.
Anyway this solution do not looks "elegant" and I would like to avoid.


Can anyone suggest a good method how to cope with this issue ?
-- 
Pozdrawiam/Best regards/Mit freundlichen Grüßen, Tomasz Majchrowski,
Information Technology and Services Consultant and Contractor