.. _readme-chplenv: Setting up Your Environment for Chapel ====================================== To get started with Chapel, there are three environment settings that are strongly recommended for effective use of the release, and a number of other optional settings that are useful for cross-compiling or overriding the default settings. To check the values of the Chapel environment variables that are set or can be inferred, run the script:: $CHPL_HOME/util/printchplenv The ``setchplenv.*`` source scripts in the ``$CHPL_HOME/util/quickstart/`` and ``$CHPL_HOME/util/`` directories contain commands that set the following variables for various shells and host platforms when they are sourced from the ``$CHPL_HOME`` directory. Frequent Chapel users may want to add such settings to their shell's dotfile(s); but for getting started the setchplenv.* scripts can be convenient. .. contents:: .. _readme-chplenv.recommended_settings: Recommended Settings -------------------- .. _readme-chplenv.CHPL_HOME: CHPL_HOME ~~~~~~~~~ Setting ``CHPL_HOME`` is important if you have not installed Chapel and are instead working from a source directory. In that event, set the ``CHPL_HOME`` environment variable to point to the location of the chapel/ directory that was created when you unpacked the release. For example: .. code-block:: sh export CHPL_HOME=~/chapel-1.23.0 .. note:: This, and all other examples in the Chapel documentation, assumes you're using the ``bash`` shell. If using ``csh`` or ``tcsh``, mentally change ``export FOO=BAR`` to ``setenv FOO BAR``. If using some other shell, make the appropriate adjustment. PATH ~~~~ Updating ``PATH`` is important if you have not installed Chapel and are instead working from a source directory. Otherwise it might be necessary to use the full path to ``chpl`` when compiling programs. In that event, you can set path using the following command: .. code-block:: sh CHPL_BIN_SUBDIR=`"$CHPL_HOME"/util/chplenv/chpl_bin_subdir.py` export PATH="$PATH":"$CHPL_HOME/bin/$CHPL_BIN_SUBDIR" MANPATH ~~~~~~~ Updating ``MANPATH`` is important if you have not installed Chapel and are instead working from a source directory. Set your man path to include the directory ``$CHPL_HOME/man``. For example: .. code-block:: sh export MANPATH="$MANPATH":"$CHPL_HOME"/man Optional Settings ----------------- .. _readme-chplenv.CHPL_HOST_PLATFORM: CHPL_HOST_PLATFORM ~~~~~~~~~~~~~~~~~~ You can set the ``CHPL_HOST_PLATFORM`` environment variable to represent the platform on which you're working. For standard UNIX workstations, the default is sufficient, and is equivalent to .. code-block:: sh export CHPL_HOST_PLATFORM=`$CHPL_HOME/util/chplenv/chpl_platform.py` For other platforms that appear very similar to a UNIX workstation from the shell prompt (e.g., a Cray CS\ |trade|), the value may need to be set explicitly. The strings for our currently-supported host platforms are as follows: =========== ================================== Value Description =========== ================================== cygwin32 x86 Cygwin (Windows) platforms cygwin64 x86_64 Cygwin (Windows) platforms darwin Macintosh OS X platforms linux32 32-bit Linux platforms linux64 64-bit Linux platforms netbsd32 32-bit NetBSD platforms netbsd64 64-bit NetBSD platforms pwr6 IBM Power6 SMP cluster sunos SunOS platforms cray-cs Cray CS\ |trade| cray-xc Cray XC\ |trade| =========== ================================== Platform-specific documentation is available for most of these platforms in :ref:`platforms-index`. The Chapel Makefiles and sources are designed to work for any UNIX-compatible environment that supports a GNU-compatible make utility. The list above represents the set of platforms that we have access to and can test easily. We are interested in making our code framework portable to other platforms -- if you are using Chapel on a platform other than the ones listed above, please refer to :ref:`platform-specific-settings` for ways to set up a Makefile for this platform. .. _readme-chplenv.CHPL_TARGET_PLATFORM: CHPL_TARGET_PLATFORM ~~~~~~~~~~~~~~~~~~~~ If you are cross-compiling for a platform other than your ``$CHPL_HOST_PLATFORM``, set the ``CHPL_TARGET_PLATFORM`` environment variable to describe that platform. See `CHPL_HOST_PLATFORM`_ above for legal values (though whether or not a given setting will support cross-compilation depends on your specific environment). .. note:: If ``CHPL_TARGET_PLATFORM`` is not set, the target platform defaults to the same value as ``$CHPL_HOST_PLATFORM``. .. _readme-chplenv.CHPL_HOST_ARCH: CHPL_HOST_ARCH ~~~~~~~~~~~~~~~~~~~ Optionally, set the ``CHPL_HOST_ARCH`` environment variable to indicate the architecture type of the current machine. Normally, the default value is sufficient. ======== ============================================================= Value Description ======== ============================================================= x86_64 64-bit AMD and Intel processors aarch64 64-bit ARM processors ======== ============================================================= If unset, the default will be computed. The command ``uname -m`` should produce the same value as the default. .. _readme-chplenv.CHPL_TARGET_ARCH: CHPL_TARGET_ARCH ~~~~~~~~~~~~~~~~~~~ Optionally, set the ``CHPL_TARGET_ARCH`` environment variable to indicate the architecture type of the target machine. See the table above for ``CHPL_HOST_ARCH`` for values this might be set to. If unset, ``CHPL_TARGET_ARCH`` will be inferred. If ``CHPL_TARGET_CPU`` is ``native``, ``unknown``, or ``none`` then ``CHPL_TARGET_ARCH`` will be set to ``CHPL_HOST_ARCH``. Otherwise, ``CHPL_TARGET_ARCH`` will be set based on the architecture type specified in ``CHPL_TARGET_CPU``. .. _readme-chplenv.CHPL_COMPILER: CHPL_*_COMPILER ~~~~~~~~~~~~~~~ Optionally, you can set ``CHPL_HOST_COMPILER`` and/or ``CHPL_TARGET_COMPILER`` to indicate the compiler suite to use in building the sources. ``CHPL_HOST_COMPILER`` is the compiler used to build the Chapel compiler itself so that it will run on ``CHPL_HOST_PLATFORM``. ``CHPL_TARGET_COMPILER`` is the compiler used to build the runtime libraries and generated code for ``CHPL_TARGET_PLATFORM``. Currently supported values are as follows: =================== =================================================== Value Description =================== =================================================== allinea The Allinea ARM compiler suite -- clang and clang++ clang The Clang compiler suite -- clang and clang++ clang-included The Clang compiler in third-party/llvm cray-prgenv-allinea The Cray PrgEnv compiler using the Allinea backend cray-prgenv-cray The Cray PrgEnv compiler using the Cray CCE backend cray-prgenv-gnu The Cray PrgEnv compiler using the GNU backend cray-prgenv-intel The Cray PrgEnv compiler using the Intel backend cray-prgenv-pgi The Cray PrgEnv compiler using the PGI backend gnu The GNU compiler suite -- gcc and g++ ibm The IBM compiler suite -- xlc and xlC intel The Intel compiler suite -- icc and icpc pgi The PGI compiler suite -- pgcc and pgc++ =================== =================================================== The default for ``CHPL_*_COMPILER`` depends on the value of the corresponding ``CHPL_*_PLATFORM`` environment variable: ============ ================================================== Platform Compiler ============ ================================================== cray-x* - gnu (for ``CHPL_HOST_COMPILER``) - cray-prgenv-$PE_ENV (for ``CHPL_TARGET_COMPILER``, where PE_ENV is set by PrgEnv-* modules) darwin clang if available, otherwise gnu pwr6 ibm other gnu ============ ================================================== If ``CHPL_HOST_PLATFORM == CHPL_TARGET_PLATFORM`` and is not ``cray-x*``, ``CHPL_TARGET_COMPILER`` will default to the same value as ``CHPL_HOST_COMPILER``. .. note:: Note that builds with :ref:`readme-llvm` (i.e. when ``CHPL_LLVM=bundled``) will build the runtime twice: once with the compiler as described above and once with clang-included. We do this in order to avoid issues in linking objects built by different compilers. .. _readme-chplenv.CHPL_TARGET_CPU: CHPL_TARGET_CPU ~~~~~~~~~~~~~~~~ Optionally, set the ``CHPL_TARGET_CPU`` environment variable to indicate that the target executable should be specialized to the given architecture when using ``--specialize`` (and ``--fast``). Valid options are: ======== ============================================================= Value Description ======== ============================================================= native The C compiler will attempt to detect the architecture on the machine that is compiling the target executable. This is a good choice if you will be running on the same machine that you are compiling on. If you are not, see the options below. unknown No specialization will be performed none No specialization will be performed (will not warn) ======== ============================================================= **Architecture-specific values** =========== ================ ================ intel amd arm =========== ================ ================ core2 k8 aarch64 nehalem k8sse3 thunderx westmere barcelona thunderx2t99 sandybridge bdver1 ivybridge bdver2 haswell bdver3 broadwell bdver4 skylake knl =========== ================ ================ These values are defined to be the same as in GCC 7: https://gcc.gnu.org/onlinedocs/gcc-7.3.0/gcc/x86-Options.html https://gcc.gnu.org/onlinedocs/gcc-7.3.0/gcc/AArch64-Options.html If you do not want ``CHPL_TARGET_CPU`` to have any effect, you can set it to either ``unknown`` or ``none``. Both will disable specialization, but the latter will not warn if ``--specialize`` is used. Setting ``CHPL_TARGET_CPU`` to an incorrect value for your processor may result in an invalid binary that will not run on the intended machine. Special care should be taken to select the lowest common denominator when running on machines with heterogeneous processor architectures. The default value for this setting will vary based on settings in your environment, in order of application these rules are: * If :ref:`CHPL_TARGET_COMPILER ` is ``cray-prgenv-*`` you do not need to set anything in ``CHPL_TARGET_CPU``. One of the ``craype-*`` modules (e.g. ``craype-sandybridge``) should be loaded to provide equivalent functionality. Once the proper module is loaded, ``CRAY_CPU_TARGET`` will have the architecture being used in it. * If ``CHPL_TARGET_COMPILER`` is ``cray``, ``pgi``, or ``ibm``, ``CHPL_TARGET_CPU`` will be set to ``none`` and no specialization will occur. * If :ref:`readme-chplenv.CHPL_COMM` is set, no attempt to set a useful value will be made and ``CHPL_TARGET_CPU`` will be ``unknown``. * If :ref:`readme-chplenv.CHPL_TARGET_PLATFORM` is ``darwin``, ``linux*``, or ``cygwin*`` ``CHPL_TARGET_CPU`` will be ``native``, passing the responsibility off to the backend C compiler to detect the specifics of the hardware. .. _readme-chplenv.CHPL_MAKE: CHPL_MAKE ~~~~~~~~~ Optionally, set the ``CHPL_MAKE`` environment variable to indicate the GNU-compatible make utility that you want the compiler back-end to invoke when compiling the generated C code. If not set, this will default to a value based on ``$CHPL_HOST_PLATFORM``: ================== ============ platform make utility ================== ============ cygwin*, darwin make linux32, linux64 gmake if available, otherwise make other gmake ================== ============ .. _readme-chplenv.CHPL_MODULE_PATH: CHPL_MODULE_PATH ~~~~~~~~~~~~~~~~ Optionally, set the ``CHPL_MODULE_PATH`` environment variable to provide a list of directories to be added to the :ref:`readme-module_search`. The value of this environment variable should be a colon-separated list of directory paths. The module search path is used to satisfy 'use' statements in the Chapel program. The complete search path can be displayed using the compiler option ``--print-search-dirs``. It will also include the compiler's standard module search paths, those introduced by the ``-M`` flag on the command line and directories containing the .chpl files named explicitly on the compiler command line. .. _readme-chplenv.CHPL_LOCALE_MODEL: CHPL_LOCALE_MODEL ~~~~~~~~~~~~~~~~~ Optionally, set the ``CHPL_LOCALE_MODEL`` environment variable to indicate the locale model you want to use. Current options are: ======== ============================================= Value Description ======== ============================================= flat top-level locales are not further subdivided numa top-level locales are further subdivided into sublocales, each one a NUMA domain ======== ============================================= If unset, ``CHPL_LOCALE_MODEL`` defaults to ``flat``. See :ref:`readme-localeModels` for more information about locale models. .. _readme-chplenv.CHPL_TASKS: CHPL_TASKS ~~~~~~~~~~ Optionally, set the ``CHPL_TASKS`` environment variable to indicate what tasking layer you want to use to implement intra-locale parallelism (see :ref:`readme-tasks` for more information on this option). Current options are: ============== =================================================== Value Description ============== =================================================== qthreads use Sandia's Qthreads package fifo use POSIX threads ============== =================================================== If ``CHPL_TASKS`` is not set it defaults to ``qthreads`` in all cases except for a few specific configurations in which it defaults to ``fifo``: * target platform is ``cygwin*`` * target platform is ``netbsd*`` .. note:: Note that the Chapel ``util/quickstart/setchplenv.*`` source scripts set ``CHPL_TASKS`` to ``fifo`` to reduce build-time and third-party dependences, while the ``util/setchplenv.*`` versions leave it unset, resulting in the behavior described just above. See :ref:`readme-tasks` for more information about executing using the various ``CHPL_TASKS`` options. .. _readme-chplenv.CHPL_COMM: CHPL_COMM ~~~~~~~~~ Optionally, set the ``CHPL_COMM`` environment variable to indicate what communication layer you want to use to implement inter-locale communication. Current options are: ======= ============================================ Value Description ======= ============================================ none only supports single-locale execution gasnet use the GASNet-based communication layer ofi use the (preliminary) libfabric-based communication layer ugni Cray-specific native communication layer ======= ============================================ If unset, ``CHPL_COMM`` defaults to ``none`` in most cases. On Cray XC systems it defaults to ``ugni``. On Cray CS systems it defaults to ``gasnet``. See :ref:`readme-multilocale` for more information on executing Chapel programs using multiple locales. See :ref:`readme-libfabric` for more information about the ofi communication layer. See :ref:`readme-cray` for more information about Cray-specific runtime layers. .. _readme-chplenv.CHPL_MEM: CHPL_MEM ~~~~~~~~ Optionally, the ``CHPL_MEM`` environment variable can be used to select a memory management layer. Current options are: ========= ======================================================= Value Description ========= ======================================================= cstdlib use the standard C malloc/free commands jemalloc use Jason Evan's memory allocator ========= ======================================================= If unset, ``CHPL_MEM`` defaults to ``jemalloc`` for most configurations. If the target platform is ``cygwin*`` it defaults to ``cstdlib`` .. note:: Certain ``CHPL_COMM`` settings (e.g. ugni, gasnet segment fast/large, ofi with the gni provider) register the heap to improve communication performance. Registering the heap requires special allocator support that not all allocators provide. Currently only ``jemalloc`` is capable of supporting configurations that require a registered heap. .. _readme-chplenv.CHPL_LAUNCHER: CHPL_LAUNCHER ~~~~~~~~~~~~~ Optionally, the ``CHPL_LAUNCHER`` environment variable can be used to select a launcher to get your program up and running. See :ref:`readme-launcher` for more information on this variable's default and possible settings. .. _readme-chplenv.CHPL_ATOMICS: CHPL_ATOMICS ~~~~~~~~~~~~ Optionally, the ``CHPL_ATOMICS`` environment variable can be used to select an implementation for atomic operations in the runtime. Current options are: =========== ===================================================== Value Description =========== ===================================================== cstdlib implement atomics with C standard atomics (from C11) intrinsics implement atomics with target compiler intrinsics locks implement atomics with mutexes =========== ===================================================== If ``CHPL_ATOMICS`` is not set, it defaults to ``cstdlib`` when the target compiler is ``gnu``, ``clang``, ``allinea``, ``clang-included``, or ``cray``. It defaults to ``intrinsics`` when the target compiler is ``intel``. It defaults to ``locks`` when the target compiler is ``pgi``. See the Chapel Language Specification for more information about atomic operations in Chapel or :ref:`readme-atomics` for more information about the runtime implementation. .. _readme-chplenv.CHPL_TIMERS: CHPL_TIMERS ~~~~~~~~~~~ Optionally, the ``CHPL_TIMERS`` environment variable can be used to select an implementation for Chapel's timers. Current options are: generic use a ``gettimeofday()``-based implementation If unset, ``CHPL_TIMERS`` defaults to ``generic`` .. _readme-chplenv.CHPL_GMP: CHPL_GMP ~~~~~~~~ Optionally, the ``CHPL_GMP`` environment variable can select between no GMP support, using the GMP distributed with Chapel in third-party, or using a system GMP. Current options are: ======= ============================================================ Value Description ======= ============================================================ system use a system install of GMP (#include gmp.h, -lgmp) none do not build GMP support into the Chapel runtime bundled use the GMP distribution bundled with Chapel in third-party gmp deprecated - use bundled instead ======= ============================================================ If unset, Chapel will attempt to build GMP using :ref:`CHPL_TARGET_COMPILER` (noting that the bundled version may not be supported by all compilers). Based on the outcome, Chapel will default to: ======= ==================================================== Value Description ======= ==================================================== bundled if the build was successful system if unsuccessful and :ref:`readme-chplenv.CHPL_TARGET_PLATFORM` is cray-x* none otherwise ======= ==================================================== .. note:: Note that the Chapel ``util/quickstart/setchplenv.*`` source scripts set ``CHPL_GMP`` to ``none`` while the ``util/setchplenv.*`` versions leave it unset, resulting in the behavior described just above. .. _readme-chplenv.CHPL_HWLOC: CHPL_HWLOC ~~~~~~~~~~ Optionally, the ``CHPL_HWLOC`` environment variable can select between no hwloc support or using the hwloc package distributed with Chapel in third-party. ======== ============================================================== Value Description ======== ============================================================== none do not build hwloc support into the Chapel runtime bundled use the hwloc distribution bundled with Chapel in third-party hwloc deprecated - use bundled instead ======== ============================================================== If unset, ``CHPL_HWLOC`` defaults to ``bundled`` if :ref:`readme-chplenv.CHPL_TASKS` is ``qthreads``. In all other cases it defaults to ``none``. In the unlikely event the bundled hwloc distribution does not build successfully, it should still be possible to use qthreads. To do this, manually set ``CHPL_HWLOC`` to ``none`` and rebuild (and please file a bug with the Chapel team.) Note that building without hwloc will have a negative impact on performance. .. (comment) CHPL_HWLOC=system is also available but it is only intended to support packaging. Using CHPL_HWLOC=system is not regularly tested and may not work for you. Chapel depends on hwloc features that are not available in all versions. For best results, we recommend using the bundled hwloc if possible. .. (comment) CHPL_JEMALLOC is not a user-facing feature .. _readme-chplenv.CHPL_JEMALLOC: CHPL_JEMALLOC ~~~~~~~~~~~~~ Optionally, the ``CHPL_JEMALLOC`` environment variable can select between no jemalloc, or using the jemalloc distributed with Chapel in third-party. This setting is intended to elaborate upon ``CHPL_MEM=jemalloc``. ======== ============================================================== Value Description ======== ============================================================== none do not build or use jemalloc bundled use the jemalloc distribution bundled with Chapel in third-party jemalloc deprecated - use bundled instead ======== ============================================================== If unset, ``CHPL_JEMALLOC`` defaults to ``bundled`` if :ref:`readme-chplenv.CHPL_MEM` is ``jemalloc``. In all other cases it defaults to ``none``. .. (comment) CHPL_JEMALLOC=system is also available but it is only intended to support packaging. Using CHPL_JEMALLOC=system is not regularly tested and may not work for you. Chapel depends on jemalloc features that are not available in all versions. For best results, we recommend using the bundled jemalloc if possible. .. (comment) CHPL_LIBFABRIC is not a user-facing feature .. _readme-chplenv.CHPL_LIBFABRIC: CHPL_LIBFABRIC ~~~~~~~~~~~~~~ Optionally, the ``CHPL_LIBFABRIC`` environment variable can select between no libfabric or using the libfabric distributed with Chapel in third-party. This setting is intended to elaborate upon ``CHPL_COMM=ofi``. ========= ============================================================== Value Description ========= ============================================================== none do not build or use libfabric bundled use the libfabric distribution bundled with Chapel in third-party libfabric deprecated - use bundled instead ========= ============================================================== If unset, ``CHPL_LIBFABRIC`` defaults to ``bundled`` if :ref:`readme-chplenv.CHPL_COMM` is ``ofi``. In all other cases it defaults to ``none``. .. (comment) CHPL_LIBFABRIC=system is also available but it is only intended to support packaging. Using CHPL_LIBFABRIC=system is not regularly tested and may not work for you. Chapel depends on libfabric features that are not available in all versions. For best results, we recommend using the bundled libfabric if possible. .. _readme-chplenv.CHPL_REGEXP: CHPL_REGEXP ~~~~~~~~~~~ Optionally, the ``CHPL_REGEXP`` environment variable can be used to enable regular expression operations as defined in :chpl:mod:`Regexp`. Current options are: ======= ============================================== Value Description ======= ============================================== re2 use the re2 distribution in third-party none do not support regular expression operations ======= ============================================== If unset, Chapel will attempt to build RE2 using :ref:`CHPL_TARGET_COMPILER` (noting that the bundled version may not be supported by all compilers). Based on the outcome, Chapel will default to: ======= =============================== Value Description ======= =============================== re2 if the build was successful none otherwise ======= =============================== .. note:: Note that the Chapel ``util/quickstart/setchplenv.*`` source scripts set ``CHPL_REGEXP`` to ``'none`` while the ``util/setchplenv.*`` versions leave it unset, resulting in the behavior described just above. .. _readme-chplenv.CHPL_AUX_FILESYS: CHPL_AUX_FILESYS ~~~~~~~~~~~~~~~~ Optionally, the ``CHPL_AUX_FILESYS`` environment variable can be used to request runtime support for certain filesystems. ====== ====================================================== Value Description ====== ====================================================== none only support traditional Linux filesystems lustre enable I/O improvements specific to Lustre filesystems ====== ====================================================== If unset, ``CHPL_AUX_FILESYS`` defaults to ``none``. .. _readme-chplenv.CHPL_LLVM: CHPL_LLVM ~~~~~~~~~ Optionally, the ``CHPL_LLVM`` environment variable can be used to enable support for the LLVM back-end to the Chapel compiler (see :ref:`readme-llvm`) or to support extern blocks in Chapel code via the Clang compiler (see :ref:`readme-extern`). Current options are: ============== ====================================================== Value Description ============== ====================================================== bundled use the llvm/clang distribution in third-party llvm deprecated - use bundled instead system find a compatible LLVM in system libraries; note: the LLVM must be a version supported by Chapel none do not support llvm/clang-related features ============== ====================================================== .. (comment) -minimal can be used but is only interesting for developers llvm-minimal as above, but only build and link LLVM ADTs system-minimal as above, but only link LLVM ADTs If unset, ``CHPL_LLVM`` defaults to ``bundled`` if you've already installed llvm in third-party and ``none`` otherwise. Chapel currently supports LLVM 10.0. .. note:: We have had success with this procedure to install LLVM 10.0 dependencies on Ubuntu. First, follow the instructions at ``https://apt.llvm.org`` that explain how to place the appropriate lines into ``/etc/apt/sources.list.d/llvm-toolchain.list`` and retrieve the archive signature, then do the following. .. code-block:: sh apt-get install llvm-10-dev llvm-10 llvm-10-tools clang-10 libclang-10-dev libedit-dev .. _readme-chplenv.CHPL_UNWIND: CHPL_UNWIND ~~~~~~~~~~~ Optionally, the ``CHPL_UNWIND`` environment variable can be used to select an unwind library for stack tracing. Current options are: ========= ======================================================= Value Description ========= ======================================================= bundled use the libunwind bundled with Chapel in third-party libunwind deprecated - use bundled instead system assume libunwind is already installed on the system none don't use an unwind library, disabling stack tracing ========= ======================================================= If unset, ``CHPL_UNWIND`` defaults to ``none`` .. _readme-chplenv.CHPL_LIB_PIC: CHPL_LIB_PIC ~~~~~~~~~~~~ Optionally, the ``CHPL_LIB_PIC`` environment variable can be used to build position independent or position dependent code. This is intended for use when :ref:`readme-libraries`, especially when :ref:`readme-libraries.Python` or when building with ``--dynamic``. Current options are: ===== ================================ Value Description ===== ================================ pic build position independent code none build position dependent code ===== ================================ If unset, ``CHPL_LIB_PIC`` defaults to ``none`` .. _readme-chplenv.character_set: Character Set ------------- Chapel works with the Unicode character set with UTF-8 encoding and the traditional C collating sequence. Users are responsible for making sure that they are running Chapel in a suitable environment. For example, for `en_US` locale, the following environment variables should be set: .. code-block:: sh LANG=en_US.UTF-8 LC_COLLATE=C LC_ALL="" .. note:: Other character sets may be supported in the future. Compiler Command Line Option Defaults ------------------------------------- Most of the compiler's command line options support setting a default value for the option via an environment variable. To see a list of the environment variables that support each option, run the compiler with the ``--help-env`` flag. For boolean flags and toggles, setting the environment variable to any value selects that flag. .. _readme-chplenv.chplconfig: Chapel Configuration File ------------------------- The Chapel configuration file is a file named either ``chplconfig`` or ``.chplconfig`` that can store overrides of the inferred environment variables listed as a result of executing ``printchplenv``. Syntax ~~~~~~ Below are the valid forms of syntax for Chapel configuration files. All other usages will result in a syntax error. **Definitions** Users can define variables with the following format: .. code-block:: python CHPL_ENV=value Above, the default value of ``CHPL_ENV`` will be overridden to be ``value``. All white space is stripped away from definitions. **Ignored Lines** Any lines containing nothing or only white space will be ignored. Comments, which are denoted by the ``#`` character, similar to ``bash`` or ``python``, are also ignored. Example ~~~~~~~ Below is an example of a Chapel configuration file with comments: .. code-block:: python # ~/.chplconfig # Default to multi-locale CHPL_COMM=gasnet CHPL_TASKS=qthreads # Use Qthreads # System GMP is available on these machines CHPL_GMP=system To confirm the configuration file is written correctly, you can run ``printchplenv --all --overrides``, which will show a list of variables that are currently being overridden. Values followed by a ``+`` have been overridden by the Chapel configuration file, whereas values followed by a ``*`` have been overridden by an environment variable. Generating Configuration Files ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To generate a configuration file based on the current configuration, use ``printchplenv`` or ``./configure``. When using ``printchplenv``, run it with the ``--simple`` format flag to get a format compatible with Chapel configuration files. The ``--overrides`` filter flag can be used to print only the variables currently overridden by either environment variables or Chapel configuration file. For example, to save the current overrides into a Chapel configuration file: .. code-block:: sh printchplenv --all --simple --overrides > ~/.chplconfig The ``printchplenv --all --simple`` flag can be used to print all the variables of the current configuration. For example: .. code-block:: sh printchplenv --all --simple > ~/.chplconfig For more information on using ``printchplenv``, see the ``printchplenv -h`` output. Alternatively, the ``./configure`` script will generate a ``chplconfig`` file. See :ref:`readme-installing`. Search Paths and File Names ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Though you can put your Chapel configuration file anywhere by setting the ``$CHPL_CONFIG`` environment variable to its enclosing directory, you can also place it in your ``$HOME`` or ``$CHPL_HOME`` directory and Chapel will be able to find it. The search priority for Chapel configuration files is as follows: 1. ``$CHPL_CONFIG`` 2. ``$HOME`` (``~/``) 3. ``$CHPL_HOME`` When both a ``chplconfig`` and ``.chplconfig`` are present, the visible ``chplconfig`` will be prioritized. Only a single ``chplconfig`` file will be used. That is, as soon as a valid Chapel configuration file is found, the definitions of that file are used. .. note:: The ``$CHPL_CONFIG`` variable is the path to the *enclosing* directory - not the full path including ``chplconfig`` itself. Variable Priority ~~~~~~~~~~~~~~~~~ Variable precedence goes in the following order: 1. Explicit compiler flags: ``chpl --env=value`` 2. Environment variables: ``CHPL_ENV=value`` 3. Chapel configuration file: ``~/.chplconfig`` 4. Inferred environment variables: ``printchplenv`` .. |trade| unicode:: U+02122 .. TRADE MARK SIGN