THE FREEZE SCRIPT

=================

(Directions for Windows are at the end of this file.)

What is Freeze?

---------------

Freeze make it possible to ship arbitrary Python programs to people

who don't have Python. The shipped file (called a "frozen" version of

your Python program) is an executable, so this only works if your

platform is compatible with that on the receiving end (this is usually

a matter of having the same major operating system revision and CPU

type).

The shipped file contains a Python interpreter and large portions of

the Python run-time. Some measures have been taken to avoid linking

unneeded modules, but the resulting binary is usually not small.

The Python source code of your program (and of the library modules

written in Python that it uses) is not included in the binary --

instead, the compiled byte-code (the instruction stream used

internally by the interpreter) is incorporated. This gives some

protection of your Python source code, though not much -- a

disassembler for Python byte-code is available in the standard Python

library. At least someone running "strings" on your binary won't see

the source.

How does Freeze know which modules to include?

----------------------------------------------

Previous versions of Freeze used a pretty simple-minded algorithm to

find the modules that your program uses, essentially searching for

lines starting with the word "import". It was pretty easy to trick it

into making mistakes, either missing valid import statements, or

mistaking string literals (e.g. doc strings) for import statements.

This has been remedied: Freeze now uses the regular Python parser to

parse the program (and all its modules) and scans the generated byte

code for IMPORT instructions. It may still be confused -- it will not

know about calls to the __import__ built-in function, or about import

statements constructed on the fly and executed using the 'exec'

statement, and it will consider import statements even when they are

unreachable (e.g. "if 0: import foobar").

This new version of Freeze also knows about Python's new package

import mechanism, and uses exactly the same rules to find imported

modules and packages. One exception: if you write 'from package

import *', Python will look into the __all__ variable of the package

to determine which modules are to be imported, while Freeze will do a

directory listing.

One tricky issue: Freeze assumes that the Python interpreter and

environment you're using to run Freeze is the same one that would be

used to run your program, which should also be the same whose sources

and installed files you will learn about in the next section. In

particular, your PYTHONPATH setting should be the same as for running

your program locally. (Tip: if the program doesn't run when you type

"python hello.py" there's little chance of getting the frozen version

to run.)

How do I use Freeze?

--------------------

Normally, you should be able to use it as follows:

python freeze.py hello.py

where hello.py is your program and freeze.py is the main file of

Freeze (in actuality, you'll probably specify an absolute pathname

such as /usr/joe/python/Tools/freeze/freeze.py).

What do I do next?

------------------

Freeze creates a number of files: frozen.c, config.c and Makefile,

plus one file for each Python module that gets included named

M_<module>.c. To produce the frozen version of your program, you can

simply type "make". This should produce a binary file. If the

filename argument to Freeze was "hello.py", the binary will be called

"hello".

Note: you can use the -o option to freeze to specify an alternative

directory where these files are created. This makes it easier to

clean up after you've shipped the frozen binary. You should invoke

"make" in the given directory.

Freezing Tkinter programs

-------------------------

Unfortunately, it is currently not possible to freeze programs that

use Tkinter without a Tcl/Tk installation. The best way to ship a

frozen Tkinter program is to decide in advance where you are going

to place the Tcl and Tk library files in the distributed setup, and

then declare these directories in your frozen Python program using

the TCL_LIBRARY and TK_LIBRARY environment variables.

For example, assume you will ship your frozen program in the directory

<root>/bin/windows-x86 and will place your Tcl library files

in <root>/lib/tcl8.2 and your Tk library files in <root>/lib/tk8.2. Then

placing the following lines in your frozen Python script before importing

tkinter would set the environment correctly for Tcl/Tk:

import os

import os.path

RootDir = os.path.dirname(os.path.dirname(os.getcwd()))

import sys

if sys.platform == "win32":

sys.path = ['', '..\\..\\lib\\python-2.0']

os.environ['TCL_LIBRARY'] = RootDir + '\\lib\\tcl8.2'

os.environ['TK_LIBRARY'] = RootDir + '\\lib\\tk8.2'

elif sys.platform == "linux2":

sys.path = ['', '../../lib/python-2.0']

os.environ['TCL_LIBRARY'] = RootDir + '/lib/tcl8.2'

os.environ['TK_LIBRARY'] = RootDir + '/lib/tk8.2'

elif sys.platform == "solaris":

sys.path = ['', '../../lib/python-2.0']

os.environ['TCL_LIBRARY'] = RootDir + '/lib/tcl8.2'

os.environ['TK_LIBRARY'] = RootDir + '/lib/tk8.2'

This also adds <root>/lib/python-2.0 to your Python path

for any Python files such as _tkinter.pyd you may need.

Note that the dynamic libraries (such as tcl82.dll tk82.dll python20.dll

under Windows, or libtcl8.2.so and libtcl8.2.so under Unix) are required

at program load time, and are searched by the operating system loader

before Python can be started. Under Windows, the environment

variable PATH is consulted, and under Unix, it may be the

environment variable LD_LIBRARY_PATH and/or the system

shared library cache (ld.so). An additional preferred directory for

finding the dynamic libraries is built into the .dll or .so files at

compile time - see the LIB_RUNTIME_DIR variable in the Tcl makefile.

The OS must find the dynamic libraries or your frozen program won't start.

Usually I make sure that the .so or .dll files are in the same directory

as the executable, but this may not be foolproof.

A workaround to installing your Tcl library files with your frozen

executable would be possible, in which the Tcl/Tk library files are

incorporated in a frozen Python module as string literals and written

to a temporary location when the program runs; this is currently left

as an exercise for the reader. An easier approach is to freeze the

Tcl/Tk code into the dynamic libraries using the Tcl ET code.

Of course, you can also simply require that Tcl/Tk is required on the

target installation, but be careful that the version corresponds.

There are some caveats using frozen Tkinter applications:

Under Windows if you use the -s windows option, writing

to stdout or stderr is an error.

The Tcl [info nameofexecutable] will be set to where the

program was frozen, not where it is run from.

The global variables argc and argv do not exist.

A warning about shared library modules

--------------------------------------

When your Python installation uses shared library modules such as

_tkinter.pyd, these will not be incorporated in the frozen program.

Again, the frozen program will work when you test it, but it won't

work when you ship it to a site without a Python installation.

Freeze prints a warning when this is the case at the end of the

freezing process:

Warning: unknown modules remain: ...

When this occurs, the best thing to do is usually to rebuild Python

using static linking only. Or use the approach described in the previous

section to declare a library path using sys.path, and place the modules

such as _tkinter.pyd there.

Troubleshooting

---------------

If you have trouble using Freeze for a large program, it's probably

best to start playing with a really simple program first (like the file

hello.py). If you can't get that to work there's something

fundamentally wrong -- perhaps you haven't installed Python. To do a

proper install, you should do "make install" in the Python root

directory.

Usage under Windows 95 or NT

----------------------------

Under Windows 95 or NT, you *must* use the -p option and point it to

the top of the Python source tree.

WARNING: the resulting executable is not self-contained; it requires

the Python DLL, currently PYTHON20.DLL (it does not require the

standard library of .py files though). It may also require one or

more extension modules loaded from .DLL or .PYD files; the module

names are printed in the warning message about remaining unknown

modules.

The driver script generates a Makefile that works with the Microsoft

command line C compiler (CL). To compile, run "nmake"; this will

build a target "hello.exe" if the source was "hello.py". Only the

files frozenmain.c and frozen.c are used; no config.c is generated or

used, since the standard DLL is used.

In order for this to work, you must have built Python using the VC++

(Developer Studio) 5.0 compiler. The provided project builds

python20.lib in the subdirectory pcbuild\Release of thje Python source

tree, and this is where the generated Makefile expects it to be. If

this is not the case, you can edit the Makefile or (probably better)

winmakemakefile.py (e.g., if you are using the 4.2 compiler, the

python20.lib file is generated in the subdirectory vc40 of the Python

source tree).

It is possible to create frozen programs that don't have a console

window, by specifying the option '-s windows'. See the Usage below.

Usage under macOS

-----------------

On macOS the freeze tool is not supported for framework builds.

Usage

-----

Here is a list of all of the options (taken from freeze.__doc__):

usage: freeze [options...] script [module]...

Options:

-p prefix: This is the prefix used when you ran ``make install''

in the Python build directory.

(If you never ran this, freeze won't work.)

The default is whatever sys.prefix evaluates to.

It can also be the top directory of the Python source

tree; then -P must point to the build tree.

-P exec_prefix: Like -p but this is the 'exec_prefix', used to

install objects etc. The default is whatever sys.exec_prefix

evaluates to, or the -p argument if given.

If -p points to the Python source tree, -P must point

to the build tree, if different.

-e extension: A directory containing additional .o files that

may be used to resolve modules. This directory

should also have a Setup file describing the .o files.

On Windows, the name of a .INI file describing one

or more extensions is passed.

More than one -e option may be given.

-o dir: Directory where the output files are created; default '.'.

-m: Additional arguments are module names instead of filenames.

-a package=dir: Additional directories to be added to the package's

__path__. Used to simulate directories added by the

package at runtime (eg, by OpenGL and win32com).

More than one -a option may be given for each package.

-l file: Pass the file to the linker (windows only)

-d: Debugging mode for the module finder.

-q: Make the module finder totally quiet.

-h: Print this help message.

-x module Exclude the specified module.

-i filename: Include a file with additional command line options. Used

to prevent command lines growing beyond the capabilities of

the shell/OS. All arguments specified in filename

are read and the -i option replaced with the parsed

params (note - quoting args in this file is NOT supported)

-s subsystem: Specify the subsystem (For Windows only.);

'console' (default), 'windows', 'service' or 'com_dll'

-w: Toggle Windows (NT or 95) behavior.

(For debugging only -- on a win32 platform, win32 behavior

is automatic.)

Arguments:

script: The Python script to be executed by the resulting binary.

module ...: Additional Python modules (referenced by pathname)

that will be included in the resulting binary. These

may be .py or .pyc files. If -m is specified, these are

module names that are search in the path instead.

--Guido van Rossum (home page: https://www.python.org/~guido/)