On 2019-05-24 19:38+0200 Haio Maio wrote:
Manually-specified variables were not used by the project
MY_VAR
when I call
cmake -DMY_VAR= ...
The goal is
if(NOT DEFINED MY_VAR)
...
else()
...
if()
in order to tell cmake over the command line what to do.
How to achieve this ?
This functionality just works for me (using cmake version 3.13.4).
For example, here is a simple test case:
irwin@merlin> cat /tmp/CMakeLists.txt
if(NOT DEFINED MY_VAR)
message(STATUS "MY_VAR is not DEFINED")
else()
message(STATUS "MY_VAR is DEFINED")
endif()
irwin@merlin> cmake -P /tmp/CMakeLists.txt
-- MY_VAR is not DEFINED
irwin@merlin> cmake -DMY_VAR=OFF -P /tmp/CMakeLists.txt
-- MY_VAR is DEFINED
irwin@merlin> cmake -DMY_VAR=ON -P /tmp/CMakeLists.txt
-- MY_VAR is DEFINED
So just like the documentation says at
<https://cmake.org/cmake/help/latest/command/if.html>
what is tested is whether *any* true or false value has been set. What is more
problematic
is how to make sure the variable is not set with the -D option, and the only
way I
know how to do that is the first test above (i.e., do not use -DMY_VAR=??? at
all).
I hope this simple example helps you to figure out what is going on with your
more complex
example.
Alan
__________________________
Alan W. Irwin
Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.org); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________
Linux-powered Science
__________________________
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