py_compile.compile()

py_compile.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 named file. The byte-code is written to cfile, which defaults to the PEP 3147/PEP 488 path, ending in .pyc. 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 when instead of file. If doraise is true, a 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.

If the path that cfile becomes (either explicitly specified or computed) is a symlink or non-regular file, FileExistsError will be raised. This is to act as a warning that import will turn those paths into regular files if it is allowed to write byte-compiled files to those paths. This is a side-effect of import using file renaming to place the final byte-compiled file into place to prevent concurrent file writing issues.

optimize controls the optimization level and is passed to the built-in compile() function. The default of -1 selects the optimization level of the current interpreter.

Changed in version 3.2: Changed default value of cfile to be PEP 3147-compliant. Previous default was file + 'c' ('o' if optimization was enabled). Also added the optimize parameter.

Changed in version 3.4: Changed code to use importlib for the byte-code cache file writing. This means file creation/writing semantics now match what importlib does, e.g. permissions, write-and-move semantics, etc. Also added the caveat that FileExistsError is raised if cfile is a symlink or non-regular file.

doc_python
2016-10-07 17:41:03
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