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diff --git a/libcxx/docs/UsingLibcxx.rst b/libcxx/docs/UsingLibcxx.rst new file mode 100644 index 00000000000..8de58d8659e --- /dev/null +++ b/libcxx/docs/UsingLibcxx.rst @@ -0,0 +1,89 @@ +============ +Using libc++ +============ + +.. contents:: + :local: + +Getting Started +=============== + +If you already have libc++ installed you can use it with clang. + +.. code-block:: bash + + $ clang++ -stdlib=libc++ test.cpp + $ clang++ -std=c++11 -stdlib=libc++ test.cpp + +On OS X and FreeBSD libc++ is the default standard library +and the ``-stdlib=libc++`` is not required. + +.. _alternate libcxx: + +If you want to select an alternate installation of libc++ you +can use the following options. + +.. code-block:: bash + + $ clang++ -std=c++11 -stdlib=libc++ -nostdinc++ \ + -I<libcxx-install-prefix>/include/c++/v1 \ + -L<libcxx-install-prefix>/lib \ + -Wl,-rpath,<libcxx-install-prefix>/lib \ + test.cpp + +The option ``-Wl,-rpath,<libcxx-install-prefix>/lib`` adds a runtime library +search path. Meaning that the systems dynamic linker will look for libc++ in +``<libcxx-install-prefix>/lib`` whenever the program is run. Alternatively the +environment variable ``LD_LIBRARY_PATH`` (``DYLD_LIBRARY_PATH`` on OS X) can +be used to change the dynamic linkers search paths after a program is compiled. + +An example of using ``LD_LIBRARY_PATH``: + +.. code-block:: bash + + $ clang++ -stdlib=libc++ -nostdinc++ \ + -I<libcxx-install-prefix>/include/c++/v1 + -L<libcxx-install-prefix>/lib \ + test.cpp -o + $ ./a.out # Searches for libc++ in the systems library paths. + $ export LD_LIBRARY_PATH=<libcxx-install-prefix>/lib + $ ./a.out # Searches for libc++ along LD_LIBRARY_PATH + + + +Using libc++ on Linux +===================== + +On Linux libc++ typically links to a shared version of libc++abi. Unfortunately +you can't simply run clang with "-stdlib=libc++" as clang is not set up to +link for this configuration. To get around this you'll have to manually +link libc++abi yourself. For example: + +.. code-block:: bash + + $ clang++ -stdlib=libc++ test.cpp -lc++ -lc++abi -lm -lc -lgcc_s -lgcc + +Alternately, you could just add libc++abi to your libraries list, which in +most situations will give the same result: + +.. code-block:: bash + + $ clang++ -stdlib=libc++ test.cpp -lc++abi + + +Using libc++ with GCC +--------------------- + +GCC does not provide a way to switch from libstdc++ to libc++. You must manually +configure the compile and link commands. + +In particular you must tell GCC to remove the libstdc++ include directories +using ``-nostdinc++`` and to not link libstdc++.so using ``-nodefaultlibs``. + +Note that ``-nodefaultlibs`` removes all of the standard system libraries and +not just libstdc++ so they must be manually linked. For example: + +.. code-block:: bash + + $ g++ -nostdinc++ -I<libcxx-install-prefix>/include/c++/v1 \ + test.cpp -nodefaultlibs -lc++ -lc++abi -lm -lc -lgcc_s -lgcc |