Merge topic 'doc-CMP0054-example'

9535b86d Help: Replace CMP0054 example to show when it makes a difference
This commit is contained in:
Brad King
2015-04-30 10:31:59 -04:00
committed by CMake Topic Stage

View File

@@ -16,29 +16,33 @@ Given the following partial example:
::
set(MONKEY 1)
set(ANIMAL MONKEY)
set(A E)
set(E "")
if("${ANIMAL}" STREQUAL "MONKEY")
if("${A}" STREQUAL "")
message("Result is TRUE before CMake 3.1 or when CMP0054 is OLD")
else()
message("Result is FALSE in CMake 3.1 and above if CMP0054 is NEW")
endif()
After explicit expansion of variables this gives:
::
if("MONKEY" STREQUAL "MONKEY")
if("E" STREQUAL "")
With the policy set to ``OLD`` implicit expansion reduces this semantically to:
::
if("1" STREQUAL "1")
if("" STREQUAL "")
With the policy set to ``NEW`` the quoted arguments will not be
further dereferenced:
::
if("MONKEY" STREQUAL "MONKEY")
if("E" STREQUAL "")
This policy was introduced in CMake version 3.1.
CMake version |release| warns when the policy is not set and uses