.. _best-practices-runtime-library:

==========================
The Chapel Runtime Library
==========================

Where is it?
------------

Sources:

  ``$CHPL_HOME/runtime/src``

  ``$CHPL_HOME/runtime/include``

Compiled code:

  ``$CHPL_HOME/runtime/src/gen/MORE-DIRS``

  ``$CHPL_HOME/lib/MORE-DIRS``


  `MORE-DIRS` indicate the various aspects of the configuration

  (e.g. which comm/task/threads layers were used, runtime platform, etc.)

See also:
  ``$CHPL_HOME/runtime/README``


Compiling
---------

Currently you can have only one compilation of the runtime (per configuration)
in terms of optimization, debugging support, and profiling:

::
     
      make DEBUG=1 OPTIMIZE=0   # debug support
      make DEBUG=0 OPTIMIZE=1   # optimized
      make DEBUG=0 OPTIMIZE=1 PROFILE=1   # profiling support
      make DEBUG=0 OPTIMIZE=1 WARNINGS=1  # promote backend C compiler warnings to errors


Debugging
---------

See also debugging notes in ``GeneratedCode.txt``.


Examining the source code
-------------------------

``$CHPL_HOME/runtime/TAGS``
  generated when you build the runtime

  also included in TAGS for a compiled Chapel program