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authorBrad King <brad.king@kitware.com>2017-12-06 16:06:12 (GMT)
committerBrad King <brad.king@kitware.com>2017-12-22 14:05:54 (GMT)
commit31d59ff3b104f012d5eca9e15c1558e2c67ef495 (patch)
tree6ed1348bc8805a0d13b202768a88fc6c0e23b5a5 /Source/Checks
parent31c6b9adbff0fd7113ce4b97bc4ad9514615deb8 (diff)
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Compile CMake as C++17 if supported by the compiler
Add a check that a simple source file can compile as C++17 that uses some of the features we need. Do this only when hosted by CMake 3.8 or above because those versions are aware of C++17. Check for unordered_map as we do in bootstrap since commit 375eca7881 (bootstrap: Check support for unordered_map from compiler mode, 2017-11-30). Also maintain the existing C++14 cstdio check.
Diffstat (limited to 'Source/Checks')
-rw-r--r--Source/Checks/cm_cxx17_check.cmake36
-rw-r--r--Source/Checks/cm_cxx17_check.cpp7
2 files changed, 43 insertions, 0 deletions
diff --git a/Source/Checks/cm_cxx17_check.cmake b/Source/Checks/cm_cxx17_check.cmake
new file mode 100644
index 0000000..83d3971
--- /dev/null
+++ b/Source/Checks/cm_cxx17_check.cmake
@@ -0,0 +1,36 @@
+set(CMake_CXX17_BROKEN 0)
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+ if(NOT CMAKE_CXX17_STANDARD_COMPILE_OPTION)
+ set(CMake_CXX17_WORKS 0)
+ endif()
+ if(NOT DEFINED CMake_CXX17_WORKS)
+ message(STATUS "Checking if compiler supports needed C++17 constructs")
+ try_compile(CMake_CXX17_WORKS
+ ${CMAKE_CURRENT_BINARY_DIR}
+ ${CMAKE_CURRENT_LIST_DIR}/cm_cxx17_check.cpp
+ CMAKE_FLAGS -DCMAKE_CXX_STANDARD=17
+ OUTPUT_VARIABLE OUTPUT
+ )
+ if(CMake_CXX17_WORKS AND "${OUTPUT}" MATCHES "error: no member named.*gets.*in the global namespace")
+ set_property(CACHE CMake_CXX17_WORKS PROPERTY VALUE 0)
+ endif()
+ if(CMake_CXX17_WORKS)
+ message(STATUS "Checking if compiler supports needed C++17 constructs - yes")
+ file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
+ "Determining if compiler supports needed C++17 constructs passed with the following output:\n"
+ "${OUTPUT}\n"
+ "\n"
+ )
+ else()
+ message(STATUS "Checking if compiler supports needed C++17 constructs - no")
+ file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+ "Determining if compiler supports needed C++17 constructs failed with the following output:\n"
+ "${OUTPUT}\n"
+ "\n"
+ )
+ endif()
+ endif()
+ if(NOT CMake_CXX17_WORKS)
+ set(CMake_CXX17_BROKEN 1)
+ endif()
+endif()
diff --git a/Source/Checks/cm_cxx17_check.cpp b/Source/Checks/cm_cxx17_check.cpp
new file mode 100644
index 0000000..2cbf1d5
--- /dev/null
+++ b/Source/Checks/cm_cxx17_check.cpp
@@ -0,0 +1,7 @@
+#include <cstdio>
+#include <unordered_map>
+
+int main()
+{
+ return 0;
+}