[cmake-developers] Review Request: Automatically link to libqtmain on Windows

[Stephen Kelly]

Brad King wrote:

> On 01/16/2013 12:15 PM, Stephen Kelly wrote:
>> Good point. I've updated the topic on my gitorious clone, and tested that
>> it works on Windows. (It required a small fix to a previous topic too).
> 
> Thanks.  In this expression:
> 
>  +
>  $<$<AND:${_isExe},${_isWin32},${_isPolicyNEW},
${_isNotExcluded}>:Qt4::qtmain>
> 
> the AND will short-circuit and skip the policy if it is not needed, right?

The policy will not be checked for non WIN32_EXECUTABLES, but for those 
targets it will be checked.

As it was, it is also checked even if QT4_NO_LINK_QTMAIN is set, which I  
have now changed.

> 
> In the docs of the new property:
> 
> +  "  $<TARGET_POLICY:pol>          = '1' if the policy was NEW when "   \
> +  "the 'head' target was created, else '0'.  If the policy was WARN, "  \
> +  "the warning message for the policy will be emitted. This generator " \
> +  "expression only works for a subset of policies.\n"                   \
> 
> we can't say "WARN" here.  That is an internal implementation detail.  In
> documentation it means "policy is not set".

Fixed now.

> 
> Also please add a test for the new expression and its error cases.
> 
>> I wonder if I should/can make this policy 'Qt' specific rather than 'Qt4'
>> specific.
>> 
>> That would allow me to use the same generator expression in the Qt 5
>> implementation of this patch, and allow for 'policy behaviour
>> compatibility' across the Qt versions. Creating a policy that can be
>> interpreted as technically referring to code outside of the cmake repo is
>> also something that has probably not been done before. I'd only be
>> checking it in the same way from the Qt 5 config file anyway.
> 
> Since the policy is being added for something inside CMake and the
> $<TARGET_POLICY> generator expression is general-purpose I see no
> reason not to use it in outside code for the same purpose.  Just
> make sure the documentation and warning messages are worded such
> that someone encountering them with Qt5 will not be confused.

Ok, 'ambiguated' now.

Thanks,

Steve.