I had been erroneously using this command, which failed at the link step:
$ clang -std=c++11 -stdlib=libc++ myInputFile.cpp
Can anyone explain why clang provides a C++ language option, and why it fails to link? Why don't the options -x c++ or -std=c++11 accomplish the same thing as clang++? Thanks!
Technically, neither of the programs named clang or clang++ is a compiler: they are both drivers that analyze the input arguments and determine what compilers/assemblers/linkers to invoke on what files with what command line arguments. The only difference between the two is that clang links against only the C standard library if it performs a link, whereas clang++ links against both the C++ and C standard libraries.
The -x=<language> option overrides the driver programs' heuristics for determining source file language, it directs the driver to invoke the compiler for <language> regardless.
The -std=<dialect> option picks which dialect of a particular language you want to use. If you need to ensure that your C++ program is portable to an old C++98 compiler, you can compile it with -std=c++98. -std only applies to the target language: it won't try to compile e.g. assembler or java as C++98, only source files that the driver believes to be C++.
In short, there are two different driver programs to make it easy to select which libraries to link against. There are reasonable use cases for compiling C++ but not linking against the C++ standard library.
Clang is the name of the whole compiler.
However, from a command-line point of view:
- Clang is the C compiler
- Clang++ is the C++ compiler (like g++ is a C++ compiler, whereas gcc is a C compiler)
The -std=c++11 option enables the new C++11 standard (as in g++).
来源：https://stackoverflow.com/questions/20047218/what-is-the-difference-clang-clang-std-c11