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