:mod:`py_compile` --- Compile Python source files
=================================================

.. module:: py_compile
   :synopsis: Generate byte-code files from Python source files.
.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
.. documentation based on module docstrings

.. index:: pair: file; byte-code

The :mod:`py_compile` module provides a function to generate a byte-code file
from a source file, and another function used when the module source file is
invoked as a script.

Though not often needed, this function can be useful when installing modules for
shared use, especially if some of the users may not have permission to write the
byte-code cache files in the directory containing the source code.


.. exception:: PyCompileError

   Exception raised when an error occurs while attempting to compile the file.


.. function:: compile(file, cfile=None, dfile=None, doraise=False, optimize=-1)

   Compile a source file to byte-code and write out the byte-code cache  file.  The
   source code is loaded from the file name *file*.  The  byte-code is written to
   *cfile*, which defaults to the :PEP:`3147` path, ending in ``.pyc``
   (``'.pyo`` if optimization is enabled in the current interpreter).  For
   example, if *file* is ``/foo/bar/baz.py`` *cfile* will default to
   ``/foo/bar/__pycache__/baz.cpython-32.pyc`` for Python 3.2.  If *dfile* is specified, it is used as the
   name of the source file in error messages instead of *file*.  If *doraise* is
   true, a :exc:`PyCompileError` is raised when an error is encountered while
   compiling *file*. If *doraise* is false (the default), an error string is
   written to ``sys.stderr``, but no exception is raised.  This function
   returns the path to byte-compiled file, i.e. whatever *cfile* value was
   used.

   *optimize* controls the optimization level and is passed to the built-in
   :func:`compile` function.  The default of ``-1`` selects the optimization
   level of the current interpreter.

   .. versionchanged:: 3.2
      Added the *optimize* parameter.


.. function:: main(args=None)

   Compile several source files.  The files named in *args* (or on the command
   line, if *args* is ``None``) are compiled and the resulting bytecode is
   cached in the normal manner.  This function does not search a directory
   structure to locate source files; it only compiles files named explicitly.

When this module is run as a script, the :func:`main` is used to compile all the
files named on the command line.  The exit status is nonzero if one of the files
could not be compiled.


.. seealso::

   Module :mod:`compileall`
      Utilities to compile all Python source files in a directory tree.