sam-t2/devtools/v9/html/python/ext/win-dlls.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<link rel="STYLESHEET" href="ext.css" type='text/css' />
<link rel="SHORTCUT ICON" href="../icons/pyfav.png" type="image/png" />
<link rel='start' href='../index.html' title='Python Documentation Index' />
<link rel="first" href="ext.html" title='Extending and Embedding the Python Interpreter' />
<link rel='contents' href='contents.html' title="Contents" />
<link rel='last' href='about.html' title='About this document...' />
<link rel='help' href='about.html' title='About this document...' />
<link rel="prev" href="dynamic-linking.html" />
<link rel="parent" href="building-on-windows.html" />
<link rel="next" href="embedding.html" />
<meta name='aesop' content='information' />
<title>4.3 Using DLLs in Practice </title>
</head>
<body>
<DIV CLASS="navigation">
<div id='top-navigation-panel' xml:id='top-navigation-panel'>
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="4.2 Differences Between Unix"
  href="dynamic-linking.html"><img src='../icons/previous.png'
  border='0' height='32'  alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="4. Building C and"
  href="building-on-windows.html"><img src='../icons/up.png'
  border='0' height='32'  alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="5. Embedding Python in"
  href="embedding.html"><img src='../icons/next.png'
  border='0' height='32'  alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Extending and Embedding the Python Interpreter</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
  href="contents.html"><img src='../icons/contents.png'
  border='0' height='32'  alt='Contents' width='32' /></A></td>
<td class='online-navigation'><img src='../icons/blank.png'
  border='0' height='32'  alt='' width='32' /></td>
<td class='online-navigation'><img src='../icons/blank.png'
  border='0' height='32'  alt='' width='32' /></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="dynamic-linking.html">4.2 Differences Between Unix</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="building-on-windows.html">4. Building C and</A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="embedding.html">5. Embedding Python in</A>
</div>
<hr /></div>
</DIV>
<!--End of Navigation Panel-->

<H1><A NAME="SECTION006300000000000000000"></A><A NAME="win-dlls"></A>
<BR>
4.3 Using DLLs in Practice
</H1>

<P>
Windows Python is built in Microsoft Visual C++; using other
compilers may or may not work (though Borland seems to).  The rest of
this section is MSVC++ specific.

<P>
When creating DLLs in Windows, you must pass <span class="file">pythonXY.lib</span> to
the linker.  To build two DLLs, spam and ni (which uses C functions
found in spam), you could use these commands:

<P>
<div class="verbatim"><pre>
cl /LD /I/python/include spam.c ../libs/pythonXY.lib
cl /LD /I/python/include ni.c spam.lib ../libs/pythonXY.lib
</pre></div>

<P>
The first command created three files: <span class="file">spam.obj</span>,
<span class="file">spam.dll</span> and <span class="file">spam.lib</span>.  <span class="file">Spam.dll</span> does not contain
any Python functions (such as <tt class="cfunction">PyArg_ParseTuple()</tt>), but it
does know how to find the Python code thanks to <span class="file">pythonXY.lib</span>.

<P>
The second command created <span class="file">ni.dll</span> (and <span class="file">.obj</span> and
<span class="file">.lib</span>), which knows how to find the necessary functions from
spam, and also from the Python executable.

<P>
Not every identifier is exported to the lookup table.  If you want any
other modules (including Python) to be able to see your identifiers,
you have to say "<tt class="samp">_declspec(dllexport)</tt>", as in "<tt class="samp">void
_declspec(dllexport) initspam(void)</tt>" or "<tt class="samp">PyObject
_declspec(dllexport) *NiGetSpamData(void)</tt>".

<P>
Developer Studio will throw in a lot of import libraries that you do
not really need, adding about 100K to your executable.  To get rid of
them, use the Project Settings dialog, Link tab, to specify
<em>ignore default libraries</em>.  Add the correct
<span class="file">msvcrt<var>xx</var>.lib</span> to the list of libraries.

<DIV CLASS="navigation">
<div class='online-navigation'>
<p></p><hr />
<table align="center" width="100%" cellpadding="0" cellspacing="2">
<tr>
<td class='online-navigation'><a rel="prev" title="4.2 Differences Between Unix"
  href="dynamic-linking.html"><img src='../icons/previous.png'
  border='0' height='32'  alt='Previous Page' width='32' /></A></td>
<td class='online-navigation'><a rel="parent" title="4. Building C and"
  href="building-on-windows.html"><img src='../icons/up.png'
  border='0' height='32'  alt='Up One Level' width='32' /></A></td>
<td class='online-navigation'><a rel="next" title="5. Embedding Python in"
  href="embedding.html"><img src='../icons/next.png'
  border='0' height='32'  alt='Next Page' width='32' /></A></td>
<td align="center" width="100%">Extending and Embedding the Python Interpreter</td>
<td class='online-navigation'><a rel="contents" title="Table of Contents"
  href="contents.html"><img src='../icons/contents.png'
  border='0' height='32'  alt='Contents' width='32' /></A></td>
<td class='online-navigation'><img src='../icons/blank.png'
  border='0' height='32'  alt='' width='32' /></td>
<td class='online-navigation'><img src='../icons/blank.png'
  border='0' height='32'  alt='' width='32' /></td>
</tr></table>
<div class='online-navigation'>
<b class="navlabel">Previous:</b>
<a class="sectref" rel="prev" href="dynamic-linking.html">4.2 Differences Between Unix</A>
<b class="navlabel">Up:</b>
<a class="sectref" rel="parent" href="building-on-windows.html">4. Building C and</A>
<b class="navlabel">Next:</b>
<a class="sectref" rel="next" href="embedding.html">5. Embedding Python in</A>
</div>
</div>
<hr />
<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
</DIV>
<!--End of Navigation Panel-->
<ADDRESS>
See <i><a href="about.html">About this document...</a></i> for information on suggesting changes.
</ADDRESS>
</BODY>
</HTML>