[CMake] add_library/add_executable ordering

[Bill Hoffman]

Tyler Roscoe wrote:
> On Wed, Jun 24, 2009 at 03:30:33PM -0700, Hai Nguyen wrote:
>> add_library( libB ... )
>> add_executable( ExecB ... )
>> target_link_libraries( ExecB libB )
>>
>> but the build order now is: ExecB, libB
>>
>> I'm getting link errors because libB doesn't exist yet. If I comment out the
>> ExecB stuff, it builds libB.
>>
>> Can someone give me a clue on what criteria CMake is using to determine what
>> builds first?
> 
> I think the order is undefined unless there are dependencies to resolve.
> 
> I'm a litle surprised that your B example doesn't work, since I thought
> CMake was smart enough to notice that execB needs libB and would thus
> build libB first.
> 
> Anyway, the way to get the correct build order is by using
> add_dependencies(). If you do add_dependencies(execB libB) then
> everything should work as expected.
> 

I don't think your example is complete.   That should work fine, and you 
do not need add_dependencies ever for library to executable stuff.

-Bill