[CMake] empty list evaluates to false?

[Stuermer, Michael SP/HZA-ZSEP]

You can check for existence of a variable and you can invert the result of the evaluation:

if(DEFINED <varname>)
	# called if variable exists, never mind if it's empty or not
endif()

if(NOT DEFINED <varname>)
	# called if variable is not defined
endif()

if(NOT <varname>)
	# called if variable is empty/false/off
endif()

I think it should be possible to get the expected behavior this way...

best regards,
Michael

> -----Original Message-----
> From: CMake [mailto:cmake-bounces at cmake.org] On Behalf Of ?? Jan
> Hegewald
> Sent: Monday, February 29, 2016 3:12 PM
> To: cmake at cmake.org
> Subject: [CMake] empty list evaluates to false?
> 
> Hi cmakers,
> can I create an empty list which evaluates to true? The way I tried they
> evaluate to false:
> 
> set(BLAS_LIBRARIES "") # trying to create an empty list
> if(BLAS_LIBRARIES)
> 	# not called
> endif()
> 
> Cheers,
> Jan
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