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author | 2016-09-03 18:39:32 +0000 | |
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committer | 2016-09-03 18:39:32 +0000 | |
commit | fe1ccca2776129541f1c4f645e4d1de89a22a031 (patch) | |
tree | 8e4fd7a09a5a15a9498fd2d88dcddbd40e999c79 /lib/libcxx/docs/UsingLibcxx.rst | |
parent | Fixed missing null check in switchctl.c (diff) | |
download | wireguard-openbsd-fe1ccca2776129541f1c4f645e4d1de89a22a031.tar.xz wireguard-openbsd-fe1ccca2776129541f1c4f645e4d1de89a22a031.zip |
Import libc++ 3.9.0
Diffstat (limited to 'lib/libcxx/docs/UsingLibcxx.rst')
-rw-r--r-- | lib/libcxx/docs/UsingLibcxx.rst | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/lib/libcxx/docs/UsingLibcxx.rst b/lib/libcxx/docs/UsingLibcxx.rst new file mode 100644 index 00000000000..514ed14b746 --- /dev/null +++ b/lib/libcxx/docs/UsingLibcxx.rst @@ -0,0 +1,125 @@ +============ +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++experimental and ``<experimental/...>`` +===================================================== + +Libc++ provides implementations of experimental technical specifications +in a separate library, ``libc++experimental.a``. Users of ``<experimental/...>`` +headers may be required to link ``-lc++experimental``. + +.. code-block:: bash + + $ clang++ -std=c++14 -stdlib=libc++ test.cpp -lc++experimental + +Libc++experimental.a may not always be available, even when libc++ is already +installed. For information on building libc++experimental from source see +:ref:`Building Libc++ <build instructions>` and +:ref:`libc++experimental CMake Options <libc++experimental options>`. + +Also see the `Experimental Library Implementation Status <http://libcxx.llvm.org/ts1z_status.html>`__ +page. + +.. warning:: + Experimental libraries are Experimental. + * The contents of the ``<experimental/...>`` headers and ``libc++experimental.a`` + library will not remain compatible between versions. + * No guarantees of API or ABI stability are provided. + +Using libc++ on Linux +===================== + +On Linux libc++ can typically be used with only '-stdlib=libc++'. However +some libc++ installations require the user manually link libc++abi themselves. +If you are running into linker errors when using libc++ try adding '-lc++abi' +to the link line. 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 + + +GDB Pretty printers for libc++ +------------------------------ + +GDB does not support pretty-printing of libc++ symbols by default. Unfortunately +libc++ does not provide pretty-printers itself. However there are 3rd +party implementations available and although they are not officially +supported by libc++ they may be useful to users. + +Known 3rd Party Implementations Include: + +* `Koutheir's libc++ pretty-printers <https://github.com/koutheir/libcxx-pretty-printers>`_. |