| <html> |
| <head> |
| <title>SWIG:Examples:com:simple</title> |
| </head> |
| |
| <body bgcolor="#ffffff"> |
| |
| |
| <tt>SWIG/Examples/com/simple/</tt> |
| <hr> |
| |
| <H2>Simple COM Example</H2> |
| |
| <p> |
| This example illustrates how you can hook a COM client to a very simple C program containing |
| a function and a global variable. |
| |
| <h2>The C Code</h2> |
| |
| Suppose you have the following C code: |
| |
| <blockquote> |
| <pre> |
| /* File : example.c */ |
| |
| /* A global variable */ |
| double Foo = 3.0; |
| |
| /* Compute the greatest common divisor of positive integers */ |
| int gcd(int x, int y) { |
| int g; |
| g = y; |
| while (x > 0) { |
| g = x; |
| x = y % x; |
| y = g; |
| } |
| return g; |
| } |
| </pre> |
| </blockquote> |
| |
| <h2>The SWIG interface</h2> |
| |
| Here is a simple SWIG interface file: |
| |
| <blockquote> |
| <pre> |
| /* File: example.i */ |
| %module example |
| |
| extern int gcd(int x, int y); |
| extern double Foo; |
| </pre> |
| </blockquote> |
| |
| <h2>Compilation</h2> |
| |
| <ol> |
| <li><tt>swig -com <a href="example.i">example.i</a></tt> |
| <p> |
| <li>To create the COM DLL you will need to compile the <tt>example.idl</tt> |
| file using an IDL compiler, then compile the resource file |
| <tt>example_rc.rc</tt> and finally create a DLL from |
| <tt>example_wrap.c</tt>, <tt><a href="example.c">example.c</a></tt>, |
| <tt>example.def</tt> and <tt>example_rc.res</tt>. In Visual C++ this |
| is accomplished by executing the following commands: |
| |
| <blockquote> |
| <pre> |
| midl example.idl |
| rc example_rc.rc |
| cl /LD example.c example_wrap.c example.def example_rc.res ole32.lib uuid.lib advapi32.lib oleaut32.lib |
| </pre> |
| </blockquote> |
| |
| Before using the COM DLL you will also need to register it using |
| <tt>regsvr32</tt> |
| |
| <blockquote> |
| <pre> |
| regsvr32 example.dll |
| </pre> |
| </blockquote> |
| |
| Please consult the SWIG documentation for further details. |
| </ol> |
| |
| <h2>Using the extension</h2> |
| |
| Click <a href="runme.vbs">here</a> to see a program that calls our C functions from VBScript using COM. |
| |
| <h2>Key points</h2> |
| |
| <ul> |
| <li>To access global variables and functions you need to create an object |
| of the module class. In VBScript this is done in the following way: |
| |
| <blockquote> |
| <pre> |
| Dim example |
| Set example = CreateObject("example.example") |
| </pre> |
| </blockquote> |
| |
| <li>C functions are mapped to member functions of the module class. For example: |
| <blockquote> |
| <pre> |
| Dim g |
| g = example.gcd(42,105) |
| </pre> |
| </blockquote> |
| |
| <li>C global variables are accessed as properties of the module class. For example: |
| <blockquote> |
| <pre> |
| Dim a |
| a = example.foo |
| example.foo = 20.0 |
| </pre> |
| </blockquote> |
| </ul> |
| |
| <hr> |
| </body> |
| </html> |
