| CMP0012 |
| ------- |
| |
| :command:`if` recognizes numbers and boolean constants. |
| |
| In CMake versions 2.6.4 and lower the :command:`if` command implicitly |
| dereferenced arguments corresponding to variables, even those named |
| like numbers or boolean constants, except for ``0`` and ``1``. Numbers and |
| boolean constants such as ``true``, ``false``, ``yes``, ``no``, ``on``, |
| ``off``, ``y``, ``n``, ``notfound``, ``ignore`` (all case insensitive) |
| were recognized in some cases but not all. For example, the code ``if(TRUE)`` |
| might have evaluated as ``false``. |
| Numbers such as 2 were recognized only in boolean expressions |
| like ``if(NOT 2)`` (leading to ``false``) but not as a single-argument like |
| ``if(2)`` (also leading to ``false``). Later versions of CMake prefer to |
| treat numbers and boolean constants literally, so they should not be |
| used as variable names. |
| |
| The ``OLD`` behavior for this policy is to implicitly dereference |
| variables named like numbers and boolean constants. The ``NEW`` behavior |
| for this policy is to recognize numbers and boolean constants without |
| dereferencing variables with such names. |
| |
| .. |INTRODUCED_IN_CMAKE_VERSION| replace:: 2.8.0 |
| .. |WARNS_OR_DOES_NOT_WARN| replace:: warns |
| .. include:: STANDARD_ADVICE.txt |
| |
| .. include:: DEPRECATED.txt |
