[cmake-developers] Should compile/link options be user-ordered?

[Stephen Kelly]

Brad King wrote:

> On 02/02/2014 04:12 PM, Stephen Kelly wrote:
>> I was investigating the fact that target_compile_options accepts a BEFORE
>> keyword. The keyword is ignored, by the command implementation, but could
>> be used by cmTarget. Should it be? Is the bug in target_compile_options
>> accepting the option, or in ignoring it?
>> 
>> The same question applies to the upcoming target_link_options.
> 
> Weren't you the author of the command?

Yep. If it's a bug I introduced it.

> It looks like that may have been copied from the include_directories
> command.  Does the implementation actually honor "BEFORE" anywhere?

The method

 cmTargetCompileOptionsCommand::HandleDirectContent

ignores it, so no, it is not honored. It is also not an error.

> This should just be the order within the COMPILE_OPTIONS property
> which shouldn't be too hard to implement.

Right, it's just a case of passing it from HandleDirectContent to 
InsertCompileOption. 

That's if it makes sense to handle it. I suppose there may be some flag for 
which

 target_compile_options(tgt -flag)

 # ... elsewhere:
 target_compile_options(tgt BEFORE -otherflag)

makes sense? I don't think it makes sense with -O2, -O3 for example.

Thanks,

Steve.