P/Invoke explanation

  • Thread starter Thread starter Jeroen
  • Start date Start date
J

Jeroen

Hi all,

On more than one occasion I stumbled upon an explanation here that
talks about the 'P/Invoke layer'. Although I've got a general idea
what it's about, I'm having trouble grasping what it really means.
Because I suspect I'm not the only one with these questions, here they
are on a single, new newsgroup thread:

- Can someone define what the "P/Invoke layer" is/means?
- Are there any good introductory (!) articles on this subject?

Thanks, regards,
Jeroen
 
    P/Invoke (short for platform invoke) is a term used to describe calling
functions exported from DLLs (native code, and not COM objects, that's COM
interop).
Click to expand...

And u cant use them calling java programs... please tell me I´m wrong.
looking for just that
 
Hi,


Did you google it?
I just enter P/invoke and the two first article are a good source of help.

In short P/Invoke is the feature in .NET that allows you to call unmanaged
(native WIN32) code.
 
What, call native DLL functions from Java programs? I don't believe
that is the case. I believe that you can make calls to native DLLs through
JNI.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

P/Invoke (short for platform invoke) is a term used to describe calling
functions exported from DLLs (native code, and not COM objects, that's COM
interop).
Click to expand...

And u cant use them calling java programs... please tell me I´m wrong.
looking for just that
 
Nicholas Paldino said:
What, call native DLL functions from Java programs? I don't believe
that is the case. I believe that you can make calls to native DLLs
through JNI.
Click to expand...

He said calling Java programs... presumably calling Java from .NET.

I know that with the Microsoft VM every Java class becomes a COM component,
so you could use COM interop. Though that's not likely to work with any
other VM, such as Sun.
--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

P/Invoke (short for platform invoke) is a term used to describe calling
functions exported from DLLs (native code, and not COM objects, that's
COM
interop).
Click to expand...

And u cant use them calling java programs... please tell me I´m wrong.
looking for just that
Click to expand...
 
And u cant use them calling java programs... please tell me I´m wrong.
looking for just that
Click to expand...

True.

..NET--(P/Invoke)--C--(JNI)--Java

or one of the other work arounds.

If you are willing to stretch things a bit, then http://www.ikvm.net/ !

Then you can actually run Java code within .NET - I may not want
to have an important project depend on it, but just for fun I tried
using it to call the Oracle thin JDBC driver from C# - it worked
fine.

Arne
 
I read christery as going the other way, C# -> Java. There is probably a way
with CORBA, but I usually just wrap the java codes as an app with an
input/output file API.

Nicholas Paldino said:
What, call native DLL functions from Java programs? I don't believe
that is the case. I believe that you can make calls to native DLLs through
JNI.


--
- Nicholas Paldino [.NET/C# MVP]
- (e-mail address removed)

P/Invoke (short for platform invoke) is a term used to describe calling
functions exported from DLLs (native code, and not COM objects, that's COM
interop).
Click to expand...

And u cant use them calling java programs... please tell me I´m wrong.
looking for just that
Click to expand...
 
Here are some articles that use P/Invoke to achieve various (fun) tasks with
C# beginners in mind:

http://www.geekpedia.com/tutorial176_Get-and-set-the-wave-sound-volume.html
http://www.geekpedia.com/tutorial219_Extracting-Icons-from-Files.html
http://www.geekpedia.com/tutorial177_Lock-Stand-By-Hibernate-and-Log-Off.html
http://www.geekpedia.com/tutorial209_Setting-and-Retrieving-the-Desktop-Wallpaper.html
http://www.geekpedia.com/tutorial146_Get-screen-cursor-coordinates.html
http://www.geekpedia.com/tutorial21...tem-Idle-Time-Uptime-and-Last-Input-Time.html
http://www.geekpedia.com/tutorial218_Emptying-the-Recycle-Bin-using-Csharp.html
http://www.geekpedia.com/Question12...-Caps-Lock-Num-Lock-and-Scroll-Lock-keys.html

Quite a few, eh? When you need to interact with the operating system
especially, you'll be using P/Invoke a lot, but with each new version of
..NET more functions are implemented as managed functions into the framework,
so you don't have to deal with this.

Let me know if you have questions.
 
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