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Diffstat (limited to 'Help/command/UNSET_NOTE.txt')
| -rw-r--r-- | Help/command/UNSET_NOTE.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Help/command/UNSET_NOTE.txt b/Help/command/UNSET_NOTE.txt new file mode 100644 index 0000000000..8dc912533d --- /dev/null +++ b/Help/command/UNSET_NOTE.txt @@ -0,0 +1,9 @@ +.. note:: + + When evaluating :ref:`Variable References` of the form ``${VAR}``, CMake + first searches for a normal variable with that name. If no such normal + variable exists, CMake will then search for a cache entry with that name. + Because of this, **unsetting a normal variable can expose a cache variable + that was previously hidden**. To force a variable reference of the form + ``${VAR}`` to return an empty string, use ``set(<variable> "")``, which + clears the normal variable but leaves it defined. |