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Diffstat (limited to 'lib/spack/docs/packaging_guide.rst')
| -rw-r--r-- | lib/spack/docs/packaging_guide.rst | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/lib/spack/docs/packaging_guide.rst b/lib/spack/docs/packaging_guide.rst index 34d11308f5..1b7941ab24 100644 --- a/lib/spack/docs/packaging_guide.rst +++ b/lib/spack/docs/packaging_guide.rst @@ -1803,15 +1803,15 @@ Compile-time library search paths * ``-L$dep_prefix/lib`` * ``-L$dep_prefix/lib64`` Runtime library search paths (RPATHs) - * ``-Wl,-rpath,$dep_prefix/lib`` - * ``-Wl,-rpath,$dep_prefix/lib64`` + * ``$rpath_flag$dep_prefix/lib`` + * ``$rpath_flag$dep_prefix/lib64`` Include search paths * ``-I$dep_prefix/include`` An example of this would be the ``libdwarf`` build, which has one dependency: ``libelf``. Every call to ``cc`` in the ``libdwarf`` build will have ``-I$LIBELF_PREFIX/include``, -``-L$LIBELF_PREFIX/lib``, and ``-Wl,-rpath,$LIBELF_PREFIX/lib`` +``-L$LIBELF_PREFIX/lib``, and ``$rpath_flag$LIBELF_PREFIX/lib`` inserted on the command line. This is done transparently to the project's build system, which will just think it's using a system where ``libelf`` is readily available. Because of this, you **do @@ -1831,6 +1831,31 @@ successfully find ``libdwarf.h`` and ``libdwarf.so``, without the packager having to provide ``--with-libdwarf=/path/to/libdwarf`` on the command line. +.. note:: + + For most compilers, ``$rpath_flag`` is ``-Wl,-rpath,``. However, NAG + passes its flags to GCC instead of passing them directly to the linker. + Therefore, its ``$rpath_flag`` is doubly wrapped: ``-Wl,-Wl,,-rpath,``. + ``$rpath_flag`` can be overriden on a compiler specific basis in + ``lib/spack/spack/compilers/$compiler.py``. + +Compiler flags +~~~~~~~~~~~~~~ +In rare circumstances such as compiling and running small unit tests, a package +developer may need to know what are the appropriate compiler flags to enable +features like ``OpenMP``, ``c++11``, ``c++14`` and alike. To that end the +compiler classes in ``spack`` implement the following _properties_ : +``openmp_flag``, ``cxx11_flag``, ``cxx14_flag``, which can be accessed in a +package by ``self.compiler.cxx11_flag`` and alike. Note that the implementation +is such that if a given compiler version does not support this feature, an +error will be produced. Therefore package developers can also use these properties +to assert that a compiler supports the requested feature. This is handy when a +package supports additional variants like + +.. code-block:: python + + variant('openmp', default=True, description="Enable OpenMP support.") + Message Parsing Interface (MPI) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ It is common for high performance computing software/packages to use ``MPI``. |