win32 COM and data types / direction

[Alexander Eisenhuth]

Hello everybody,

i wonder how the win32 COM extension handles different C-int types
(short, int, long). Another question for me is weather the
"out-direction" of parameter is supported "out of the box" ?

To clarify look at the methode "FunWithTwoInts "
--------------------------------------------------------------------------
#SimpleCOMServe r.py - A sample COM server - almost as small as they come!
#
# We expose a single method in a Python COM object
class PythonUtilities :
_public_methods _ = [ 'FunWithTwoInts ' ]
_reg_progid_ = "PythonDemo.Uti lities"

# NEVER copy the following ID!
# Use "print pythoncom.Creat eGuid( )" to make a new one
_reg_clsid_ = "{40CEA5F8-4D4C-4655-BD8B-0E7B6A26B556}"

def FunWithTwoInts( self, inShort, inInt, outSum):
print "got as short:%d as int:%d sum:%d" % (inShort, inInt, outSum)
outSum = inShort + inInt

# Add code so that when this script is run by
# Python.exe, it self-registers
if __name__=='__ma in_ _':
print "Registerin g COM server..."
import win32com.server .register
win32com.server .register.UseCo mmandLine(Pytho nUtilities)
--------------------------------------------------------------------------
Does anybody have experiences in this ?

Any help/hints are very welcome.

Alexander

[Thomas Heller]

Re: win32 COM and data types / direction

Alexander Eisenhuth <newsuser@staco m-software.de> writes:
[color=blue]
> Hello everybody,
>
> i wonder how the win32 COM extension handles different C-int types
> (short, int, long). Another question for me is weather the
> "out-direction" of parameter is supported "out of the box" ?
>
> To clarify look at the methode "FunWithTwoInts "
> --------------------------------------------------------------------------
> #SimpleCOMServe r.py - A sample COM server - almost as small as they come!
> #
> # We expose a single method in a Python COM object
> class PythonUtilities :
> _public_methods _ = [ 'FunWithTwoInts ' ]
> _reg_progid_ = "PythonDemo.Uti lities"
>
> # NEVER copy the following ID!
> # Use "print pythoncom.Creat eGuid( )" to make a new one
> _reg_clsid_ = "{40CEA5F8-4D4C-4655-BD8B-0E7B6A26B556}"
>
> def FunWithTwoInts( self, inShort, inInt, outSum):
> print "got as short:%d as int:%d sum:%d" % (inShort, inInt, outSum)
> outSum = inShort + inInt
>
> # Add code so that when this script is run by
> # Python.exe, it self-registers
> if __name__=='__ma in_ _':
> print "Registerin g COM server..."
> import win32com.server .register
> win32com.server .register.UseCo mmandLine(Pytho nUtilities)
> --------------------------------------------------------------------------
> Does anybody have experiences in this ?[/color]

Since there is no type library, the client code has to guess. And it
will pass the server whatever the client calls with. That could even be
a string or anything else - but why not try it out?

*IF* there is a type library that the server implements, you will get
and return what it describes.

Thomas

[Tim Roberts]

Re: win32 COM and data types / direction

Alexander Eisenhuth <newsuser@staco m-software.de> wrote:[color=blue]
>
>Hello everybody,
>
>i wonder how the win32 COM extension handles different C-int types
>(short, int, long).[/color]

All of those types are passed on the stack as 32-bit dwords. No problem.
[color=blue]
>Another question for me is weather the
>"out-direction" of parameter is supported "out of the box" ?[/color]

Yes, but you have to make them outputs from your function. Remember that
assigning to a parameter in Python does not change the parameter from the
caller's point of view:

def FunWithTwoInts( self, inShort, inInt ):
print "got as short:% as int%d" % (inShort, inInt)
return inShort + inInt

If you have multiple OUT parameters, you return a tuple of values.
[color=blue]
>To clarify look at the methode "FunWithTwoInts "
>--------------------------------------------------------------------------
>#SimpleCOMServ er.py - A sample COM server - almost as small as they come!
>#
># We expose a single method in a Python COM object
>class PythonUtilities :
> _public_methods _ = [ 'FunWithTwoInts ' ]
> _reg_progid_ = "PythonDemo.Uti lities"
>
> # NEVER copy the following ID!
> # Use "print pythoncom.Creat eGuid( )" to make a new one
> _reg_clsid_ = "{40CEA5F8-4D4C-4655-BD8B-0E7B6A26B556}"
>
> def FunWithTwoInts( self, inShort, inInt, outSum):
> print "got as short:%d as int:%d sum:%d" % (inShort, inInt, outSum)
> outSum = inShort + inInt
>
># Add code so that when this script is run by
># Python.exe, it self-registers
>if __name__=='__ma in_ _':
> print "Registerin g COM server..."
> import win32com.server .register
> win32com.server .register.UseCo mmandLine(Pytho nUtilities)
>--------------------------------------------------------------------------[/color]
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.