py_compile — Compile Python source files
Source code: Lib/py_compile.py
The 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
py_compile.
PyCompileError
Exception raised when an error occurs while attempting to compile the file.
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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 name 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 tosys.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.
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py_compile.
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 byte-code is cached in the normal manner. This function does not search a directory structure to locate source files; it only compiles files named explicitly. If‘-‘
is the only parameter in args, the list of files is taken from standard input.Changed in version 3.2: Added support for
‘-‘
.
When this module is run as a script, the 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.
See also
- Module compileall
- Utilities to compile all Python source files in a directory tree.