I didn’t know how to do this either. But after poking around in here, the getting started, and trial and error: $ ./bootstrap –with-toolset=clang $ ./b2 clean $ ./b2 toolset=clang cxxflags=”-stdlib=libc++” linkflags=”-stdlib=libc++” You’ll get lots of warnings. And the signals library will fail to build due to LWG 2059. But otherwise I think it works.
I also use Homebrew and had a similar problem on Mac OSX Maverick 10.9.5 and Xcode 6.0.1, but it was solved by running: xcode-select –install Note that it doesn’t work without the double hyphens given by the previous answer. This installs the command-line tools that also create /usr/lib/ and /usr/include/. I don’t know why Homebrew … Read more
The problem appears to be with the definition of void_t. Defining it as template<typename… Ts> struct make_void { typedef void type;}; template<typename… Ts> using void_t = typename make_void<Ts…>::type; instead yields the correct result (10) on both compilers (Demo). I believe this is the same issue noted in section 2.3 of N3911, the paper proposing void_t, … Read more
The IEEE 754-2008 Standard for Floating-Point Arithmetic and the ISO/IEC 10967 Language Independent Arithmetic (LIA) Standard, Part 1 answer why this is so. IEEE 754 ยง 6.3 The sign bit When either an input or result is NaN, this standard does not interpret the sign of a NaN. Note, however, that operations on bit strings … Read more
It is a GCC extension, called “statement expression”, described at http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html.
That’s not an intrinsic; it’s an Intel SVML library function name that confusingly uses the same naming scheme as actual intrinsics. There’s no vpowps instruction. (AVX512ER on Xeon Phi does have the semi-related vexp2ps instruction…) IDK if this naming scheme is to trick people into depending on Intel tools when writing SIMD code with their … Read more
The answer to this question doesn’t come from the standard but rather from the Itanium ABI (which is why gcc and clang have one behavior but msvc does something else). That ABI defines a layout, the relevant parts of which for the purposes of this question are: For purposes internal to the specification, we also … Read more
This is not a bug in clang, but unfortunately what the C11 standard requires. All branches of a _Generic primary expression must be a valid expressions, and thus valid under all circumstances. The fact that only one of the branches will ever be evaluated, is not related to this. Your alternative version is what C11 … Read more
As Luc Danton notes, your attempts are blocked by the rules in [expr.const]/2 which say that various expressions are not allowed in core constant expressions, including: — a reinterpret_cast — an operation that would have undefined behavior [Note: including […] certain pointer arithmetic […] — end note] The first bullet rules out your first example. … Read more
Given some C/C++ file foo.c: > clang -S -emit-llvm foo.c Produces foo.ll which is an LLVM IR file. The -emit-llvm option can also be passed to the compiler front-end directly, and not the driver by means of -cc1: > clang -cc1 foo.c -emit-llvm Produces foo.ll with the IR. -cc1 adds some cool options like -ast-print. … Read more