Clang Apple C++11 correct setup for CMake

Question

I am trying to configure CMake to compile for OS X Target.This is IMac with OS X Yosemite v 10.10.2

Clang version:

Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)

Target: x86_64-apple-darwin14.1.0

When I compile without putting any compiler flags I am getting one error for this chunk of code in one the sources:

 static const char* LogLevelStr[] {
     "TRACE  " ,
     "INFO   " ,
     "WARNING" ,
     "ERROR  " ,
     "FATAL  " ,
};

error: definition of variable with array type needs an explicit size or an initializer

I am compiling this code on Windows and GCC and it is completely fine so I don't understand why Clang complains here.So I decided,maybe I have to set C++11 support flags because I use this standard in the code a lot.

Setting

set (CMAKE_CXX_STANDARD 11)

or

set(CMAKE_CXX_FLAGS " -std=c++11")

Adds even more weird errors like these:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__bit_reference:51:52: error: expected ';' at end of declaration list _LIBCPP_INLINE_VISIBILITY operator bool() const _NOEXCEPT ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__bit_reference:87:57: error: expected ';' at end of declaration swap(__bit_reference<_Cp> __x, __bit_reference<_Cp> __y) _NOEXCEPT ^ >/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolc>hain/usr/bin/../include/c++/v1/__bit_reference:87:58: error: C++ requires a type specifier for all declarations >swap(__bit_reference<_Cp> __x, __bit_reference<_Cp> __y) _NOEXCEPT ^ >/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__config:338:21: note: expanded from macro '_NOEXCEPT' /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__bit_reference:89:10: error: expected '(' for function-style cast or type construction bool __t = __x; ~~~~ ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__bit_reference:92:2: error: expected ';' after top level declarator } ^ /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__bit_reference:1111:47: error: expected ';' at end of declaration list _LIBCPP_INLINE_VISIBILITY __bit_iterator() _NOEXCEPT

The error block from above the compiler spits at the point it is trying to parse include

Now,I tried also to set:

set(CMAKE_CXX_FLAGS "-std=c++11 -stdlib=libc++")

Same errors.

What do I miss here?

UPDATE:

I don't understand why some people marked this question for closing.Anyway,here is the problem in more details.I tried all those C++11 flags.I also added '=' to that static array.But most of the errors come after that.And it looks like root of those is .At the very first place where gets parsed it goes down into another class called __bit_reference and there at line 51 the compiler complains on the following line _LIBCPP_INLINE_VISIBILITY operator bool() const _NOEXCEPT

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__bit_reference:51:52: Expected ';' at end of declaration list

Most of the other errors are also in some ways connected to stl containers.

So my question is still valid.How do I get my source code to compile with the latest Clang on OS X including C++11 support.I am trying to do that with Xcode and have the same issues.

Xcode compiler output(some of it):

CompileC /Users/michaeliv/Library/Developer/Xcode/DerivedData/xxxxxTest-hdkkzwyyppywsjgmoyuphranqtok/Build/Intermediates/xxxxxxTest.build/Debug/xxxxxxTest.build/Objects-normal/x86_64/XXXMath.o /Users/XXXXXXX/Documents/XXXXX/xxxxxx/src/XXXMath.cpp normal x86_64 c++ com.apple.compilers.llvm.clang.1_0.compiler cd /Users/xxxxxx/Desktop/xxxxTest export LANG=en_US.US-ASCII /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -x c++ -arch x86_64 -fmessage-length=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit=0 -std=gnu++11 -stdlib=libc++ ....

I can\t put a full log as I have there also names and paths to stuff which I can't disclose.I will add more error messages above,But most of them are the same — Michael IV, Feb 04 '16 at 12:54
In that case, rename any identifiers in the log that are a confidentiality issue. No log and command line ---> No chance of an answer — marko, Feb 04 '16 at 12:58
My terminal doesn't show the full command-line of the compiler — Michael IV, Feb 04 '16 at 12:58
Really? Perhaps you should read the `cmake` documentation and learn how to turn on verbose output. — marko, Feb 04 '16 at 13:00
running make VERBOSE=1 doesn't show compiler options as well. — Michael IV, Feb 04 '16 at 13:12
This is from a clion-created project. set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11") . Maybe CMAKE_CXX_FLAGS gets overwritten? — kometen, Feb 04 '16 at 13:17
@kometen when I set this ,I still have all those errors.Though the explicit array size error is gone.But the rest of them are intact. — Michael IV, Feb 04 '16 at 13:39

score 0 · Answer 1 · edited May 23 '17 at 12:23

It's difficult to say for sure since you aren't posting a reproducible problem.

However, the code sample you posted contains a flaw:

static const char* LogLevelStr[] {
     "TRACE  " ,
     "INFO   " ,
     "WARNING" ,
     "ERROR  " ,
     "FATAL  " ,
};

should be changed to

static const char* LogLevelStr[] = {
     "TRACE  " ,
     "INFO   " ,
     "WARNING" ,
     "ERROR  " ,
     "FATAL  " ,
};

I'm not 100% on this as regards the C++11 standard, however, this is my understanding.

When you write static const char* foo[] = { "foo", "bar", "baz", }; this is aggregate initialization and not list initialization or any other kind. In your code sample, it looks like you are trying to initialize an array using C++11 list-initialization. However, to my knowledge this is not possible, and the "brace-or-equal" syntax described in chapter 8 of the standard does not apply.

This answer refers to "clause 8" to argue that list-initialization of C-style arrays is not permitted by the standard: Initializing a member array in constructor initializer

IMO that is the problem and if I were you I would use an = there, even if it would be allowed to omit it in C++11 or some future standard.

Clang Apple C++11 correct setup for CMake

1 Answers1