The unit test for this fails with GNU 4.6:
Building CXX object CMakeFiles/test_cxx_variadic_templates.dir/cxx_variadic_templates.cpp.o
CompileFeatures/cxx_variadic_templates.cpp: In static member function ‘static int Interface<I, Is>::accumulate()’:
CompileFeatures/cxx_variadic_templates.cpp:18:31: sorry, unimplemented: cannot expand ‘Is ...’ into a fixed-length argument list
CMakeFiles/test_cxx_variadic_templates.dir/build.make:54: recipe for target 'CMakeFiles/test_cxx_variadic_templates.dir/cxx_variadic_templates.cpp.o' failed
The workaround is to use a specialization:
http://stackoverflow.com/questions/1989552http://stackoverflow.com/questions/11297376
The macro is defined to 1 for GNU 4.6, and such a test is only
useful for features in language dialects newer than the
default (CXX98 for GNU currently).
Test only that it has a truthy value.
As this is not elseif(), the content has no effect.
Rather than changing it to an elseif(), remove the conditional content.
All versions of GNU prior to 5.0 default to C90/89.
Clang-C.cmake has a similar code block which correctly uses
elseif() for setting the default C dialect to C99. That may have
been updated from a C90 default at some point, so leave the
version condition there in place for now.
GNU-CXX already has complex logic and sets the _result to 0 before
tests which may set it to something else.
Change the other modules to be consistent with that.
da928d30 Help: Add notes for topic 'Apple-compiler-selection'
1f085e11 OS X: Resolve compiler in /usr/bin to that reported by Xcode xcrun
85d31735 CMakeDetermineCompiler: Factor out xcrun invocation into a macro
dcd72a74 Help: Add notes for topic 'Xcode-clang-compile-features'
3ad893b5 Features: Record for historical Xcode clang versions.
98965fb1 Features: Record dialect flags for AppleClang 4.0+.
65b81da4 cmVariableWatch: Use the cmDeleteAll algorithm with for_each.
30d2de9a cmGeneratorExpressionEvaluator: Replace own algorithm with cmDeleteAll.
4a6e795b Use the cmDeleteAll algorithm instead of trivial raw loops.
abb4a678 Add a generic algorithm for deleting items in a container.
The compiler in the PATH on mac is a stub for a different delegate
depending on the environment. Rather than requiring xcode-select to
change the used Xcode globally, users should be able to choose the
compiler per-session. That is possible with the DEVELOPER_DIR
environment variable.
However, the environment can change between running CMake and invoking
the build. In such cases, CMake prefers to record the relevant paths
from the environment and use them when invoking the build. That is not
currently done for the compilers on APPLE, so the compiler used is not
the one reported when running cmake:
$ DEVELOPER_DIR=/Applications/Xcode2.app/Contents/Developer/ cc --version
Apple LLVM version 6.0 (clang-600.0.51) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix
$ DEVELOPER_DIR=/Applications/Xcode.app/Contents/Developer/ cc --version
Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix
Update that now by querying Xcode for the correct compiler path if
the compiler located by ordinary means is located in /usr/bin.
The second hunk of commit 07d1f6fc (Features: Properly evaluate if the
compiler supports cxx_final, 2014-12-31) was a workaround for a bug in
the COMPILE_FEATURES generator expression that caused it never to return
0. Revert the workaround so we can fix the bug instead.
Revert commits:
2d738ce3 Help: Add notes for topic 'feature_record_msvc'
f73718c9 Features: Enable writing of MSVC compiler feature header.
64c30bdc Features: Record for MSVC C++ 2015 and MSVC C 2010-2015.
225c0ef8 Features: Record for MSVC 2010-2013.
This topic was merged to master prematurely, so remove it.
Brad King
Stephen Kelly
Kitware Robot