Example Python extension for Windows NT

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



This directory contains everything needed (except for the Python

distribution!) to build a Python extension module using Microsoft VC++

("Developer Studio") version 7.1.  It has been tested with VC++ 7.1 on 

Python 2.4.  You can also use earlier versions of VC to build Python 

extensions, but the sample VC project file (example.dsw in this directory) 

is in VC 7.1 format. Notice that you need to use the same compiler version

that was used to build Python itself.



COPY THIS DIRECTORY!

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

This "example_nt" directory is a subdirectory of the PC directory, in order

to keep all the PC-specific files under the same directory.  However, the

example_nt directory can't actually be used from this location.  You first

need to copy or move it up one level, so that example_nt is a direct

sibling of the PC\ and Include\ directories.  Do all your work from within

this new location -- sorry, but you'll be sorry if you don't.



OPEN THE PROJECT

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

From VC 7.1, use the

    File -> Open Solution...

dialog (*not* the "File -> Open..." dialog!).  Navigate to and select the

file "example.sln", in the *copy* of the example_nt directory you made

above.

Click Open.



BUILD THE EXAMPLE DLL

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

In order to check that everything is set up right, try building:



1. Select a configuration.  This step is optional.  Do

       Build -> Configuration Manager... -> Active Solution Configuration

   and select either "Release" or "Debug".

   If you skip this step, you'll use the Debug configuration by default.



2. Build the DLL.  Do

       Build -> Build Solution

   This creates all intermediate and result files in a subdirectory which

   is called either Debug or Release, depending on which configuration you

   picked in the preceding step.



TESTING THE DEBUG-MODE DLL

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

Once the Debug build has succeeded, bring up a DOS box, and cd to

example_nt\Debug.  You should now be able to repeat the following session

("C>" is the DOS prompt, ">>>" is the Python prompt) (note that various

debug output from Python may not match this screen dump exactly):



    C>..\..\PCbuild\python_d

    Adding parser accelerators ...

    Done.

    Python 2.2c1+ (#28, Dec 14 2001, 18:06:39) [MSC 32 bit (Intel)] on win32

    Type "help", "copyright", "credits" or "license" for more information.

    >>> import example

    [7052 refs]

    >>> example.foo()

    Hello, world

    [7052 refs]

    >>>



TESTING THE RELEASE-MODE DLL

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

Once the Release build has succeeded, bring up a DOS box, and cd to

example_nt\Release.  You should now be able to repeat the following session

("C>" is the DOS prompt, ">>>" is the Python prompt):



    C>..\..\PCbuild\python

    Python 2.2c1+ (#28, Dec 14 2001, 18:06:04) [MSC 32 bit (Intel)] on win32

    Type "help", "copyright", "credits" or "license" for more information.

    >>> import example

    >>> example.foo()

    Hello, world

    >>>



Congratulations!  You've successfully built your first Python extension

module.



CREATING YOUR OWN PROJECT

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

Choose a name ("spam" is always a winner :-) and create a directory for

it.  Copy your C sources into it.  Note that the module source file name

does not necessarily have to match the module name, but the "init" function

name should match the module name -- i.e. you can only import a module

"spam" if its init function is called "initspam()", and it should call

Py_InitModule with the string "spam" as its first argument (use the minimal

example.c in this directory as a guide).  By convention, it lives in a file

called "spam.c" or "spammodule.c".  The output file should be called

"spam.dll" or "spam.pyd" (the latter is supported to avoid confusion with a

system library "spam.dll" to which your module could be a Python interface)

in Release mode, or spam_d.dll or spam_d.pyd in Debug mode.



Now your options are:



1) Copy example.sln and example.vcproj, rename them to spam.*, and edit them

by hand.



or



2) Create a brand new project; instructions are below.



In either case, copy example_nt\example.def to spam\spam.def, and edit the

new spam.def so its second line contains the string "initspam".  If you

created a new project yourself, add the file spam.def to the project now.

(This is an annoying little file with only two lines.  An alternative

approach is to forget about the .def file, and add the option

"/export:initspam" somewhere to the Link settings, by manually editing the

"Project -> Properties -> Linker -> Command Line -> Additional Options" 

box).



You are now all set to build your extension, unless it requires other

external libraries, include files, etc.  See Python's Extending and

Embedding manual for instructions on how to write an extension.





CREATING A BRAND NEW PROJECT

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

Use the

    File -> New -> Project...

dialog to create a new Project Workspace.  Select "Visual C++ Projects/Win32/

Win32 Project", enter the name ("spam"), and make sure the "Location" is 

set to parent of the spam directory you have created (which should be a direct 

subdirectory of the Python build tree, a sibling of Include and PC).  

In "Application Settings", select "DLL", and "Empty Project".  Click OK.



You should now create the file spam.def as instructed in the previous

section. Add the source files (including the .def file) to the project, 

using "Project", "Add Existing Item".



Now open the

    Project -> spam properties...

dialog.  (Impressive, isn't it? :-) You only need to change a few

settings.  Make sure "All Configurations" is selected from the "Settings

for:" dropdown list.  Select the "C/C++" tab.  Choose the "General"

category in the popup menu at the top.  Type the following text in the

entry box labeled "Addditional Include Directories:"



    ..\Include,..\PC



Then, choose the "General" category in the "Linker" tab, and enter

    ..\PCbuild

in the "Additional library Directories" box.



Now you need to add some mode-specific settings (select "Accept"

when asked to confirm your changes):



Select "Release" in the "Configuration" dropdown list.  Click the

"Link" tab, choose the "Input" Category, and append "python24.lib" to the

list in the "Additional Dependencies" box.



Select "Debug" in the "Settings for:" dropdown list, and append

"python24_d.lib" to the list in the Additional Dependencies" box.  Then

click on the C/C++ tab, select "Code Generation", and select 

"Multi-threaded Debug DLL" from the "Runtime library" dropdown list.



Select "Release" again from the "Settings for:" dropdown list.

Select "Multi-threaded DLL" from the "Use run-time library:" dropdown list.



That's all <wink>.

