[CMake] cmake file in build directory

[Michael Jackson]

On Dec 30, 2009, at 10:48 AM, Hicham Mouline wrote:

>> -----Original Message-----
>> From: John Drescher [mailto:drescherjm at gmail.com]
>> Sent: 29 December 2009 23:16
>> To: Hicham Mouline
>> Cc: cmake at cmake.org
>> Subject: Re: [CMake] cmake file in build directory
>>
>> On Tue, Dec 29, 2009 at 6:01 PM, Hicham Mouline <hicham at mouline.org>
> wrote:
>>> Hello,
>>>
>>> I am writing software that uses boost and Qt and other 3rd party
> libraries
>> for win/mingw, win/msvc2008 and linux/gcc.
>>> The location of the 3rd party header files is different on each of  
>>> the
> boxes
>> I compile on.
>>>
>>> Is there a file to put in the build directory? Is such a file
> automatically
>> read by cmake, or does it need to be included explicitly by the  
>> source dir
>> CMakeLists.txt?
>>>
>>> Does one call the find modules explicitly? or just define for e..g
> BOOSTROOT
>> ?
>>>
>>
>> I call finders in my master CMakeLists.txt file and do not put any
>> files in any of the build trees for any of the compilers I use.
>>
>> On windows (because there is no standard library install location) a
>> lot of times this means I need to either manually find the
>> dependencies when I run cmake-gui or define BOOST_ROOT, ITK_DIR ...  
>> in
>> my environment variables.
>>
>> John
>
> Thanks,
> But I lean towards keeping all the info required to build the software
> outside of env variables, so I think I'll be able to include a
> build-specific cmake file from the build directory and set the  
> BOOST_ROOT
> there instead.
>
> That way, on boxes 1, 2 and 3, with BOOST_ROOT set appropriately on  
> each
> box, the source tree doesn't need to change.
>
> My top level CMakeLists.txt looks like:
>
> CMAKE_REQUIRED_MINIMUM...
>
> PROJECT(...)
>
> ### here I would include the build dir's cmake file
> ### this would help the Findxxx to find where the libraries reside  
> as they
> don't reside in default directories
>
> ### set up platform/compiler specific flags by
> ### including various cmake files in the source tree
>
> ADD_SUBDIRECTORY.... #for each subdir
>
> Rds,
>

Exactly how would that work? Exactly how is the "build specific cmake  
file" going to get into the build directory? So what happens if I try  
to build your project with a clean build directory? Does one have to  
hand create a file and place it in the build directory? Seems error  
prone.

   You can always just set a cmake variable either through the CMake- 
GUI application or on the command line during the invocation of cmake:

cmake -DBOOST_ROOT=C:/boost/Boost-1_41 [path to source dir]

<opinion>NOT setting environment variables is just "fighting the  
system". I fought that for a while and since most Operating systems  
don't really have an agreed upon location to install 3rd party  
libraries, let alone consistent naming of those libraries you are just  
going to waste your own time having to constantly set the cmake  
variables.
   My solution on Windows was to setup my own ".bat" file that sets my  
own environment variables, then calls the vsvars32.bat to setup visual  
studio. That is linked to a "short cut" on the desktop to invoke the  
proper "Visual Studio Command Prompt" for either 32 or 64 bit  
compilations. The setup seems to work pretty good. </opinion>

--
Mike Jackson