creating a RPC (errors) / RPC tutorial needed

Posted on 2003-11-29
Last Modified: 2012-05-04

I'm trying to create a remote procedure call in C++. I followed the steps described in the MSDN-RPC-tutorial at

I'm using Visual Studio .NET. After generating the rpc-files by midl.exe and adding them to the project, i get many linker-errors:
error LNK2001: unresolved external symbol _hello_IfHandle

extern handle_t hello_IfHandle; (variable-name without underscore) is a variable in the file hello.h, but the linker can't resolve _hello_IfHandle

error 2019: unresolved external symbol __imp_RpcBindingFree@4 refered in _main
(additional underscore)

Please help me, and tell me, what i've done wrong.
It would also be great if anyone could give me a sample of how to create a RPC.
Question by:jo_ugb
  • 3
  • 3
LVL 19

Accepted Solution

Dexstar earned 250 total points
ID: 9843862

> extern handle_t hello_IfHandle; (variable-name without underscore) is a variable
> in the file hello.h, but the linker can't resolve _hello_IfHandle

In addition the entry in the .h file, add this line to one of your .cpp files:
     handle_t hello_IfHandle;

> error 2019: unresolved external symbol __imp_RpcBindingFree@4 refered in _main

Add "Rpcrt4.lib" to your linker settings.

Hope That Helps,

Author Comment

ID: 9845590
Thanks a lot, Dex! Adding Rpcrt4.lib resolved some of the linker errors, but i had to add RpcNdr.lib too to resolve all errors.

I'll give you half of the points for that.

The rest of the points is for giving me a simple and working tutorial for creating a remote procedure call in C. - I wouldn't mind getting a link to a tutorial.
LVL 19

Expert Comment

ID: 9845606
I take it you've already seen this:

What problems are you having with that sample?

Networking for the Cloud Era

Join Microsoft and Riverbed for a discussion and demonstration of enhancements to SteelConnect:
-One-click orchestration and cloud connectivity in Azure environments
-Tight integration of SD-WAN and WAN optimization capabilities
-Scalability and resiliency equal to a data center


Author Comment

ID: 9850807
I've now found a very good and simple tutorial. It's similar to the MSDN-tutorial but easier to understand in my opinion.
You'll find the tutorial at

I'm using exactly the same code which is provided by that tutorial.
// File Example1Server.cpp ... for my rpc-server and
// File Example1Client.cpp ... for my rpc-client.

The server seems to be listening correctly but when the client calls the remote function an rpc-exception occures. I've extended the client-code of the tutorial to get the RpcExceptionCode

      puts( "now calling the server...\n\n" );
      Output((unsigned char*)"Hello RPC World!");
      unsigned long ulCode = RpcExceptionCode();
      printf( "Runtime reported exception 0x%lx = %ld\n", ulCode, ulCode );

and I get the following error-code:
Runtime reported exception 0x6a6 = 1702

That's my little problem.

I've got an additional question to the sample-program:
Why isn't the UUID needed to call the server??
The first attribute of RpcStringBindingCompose(), which represents the UUID is NULL (as well in the CodeProject-tutorial as well as in the MSDN-tutorial).

Thanks a lot for helping me!!
LVL 19

Expert Comment

ID: 9851711
Yeah, that tutorial is pretty good.  Have you seen the 2nd part to it?

As for why the UUID is not needed... On this page (, I found this quote:

"In the call to RpcStringBindingCompose, the parameters do not specify the UUID because this tutorial assumes there is just one implementation of the interface 'hello.'"

But I think it is also because when you call RpcServerRegisterIf, you also specify a NULL UUID value.



Author Comment

ID: 9852386
Ok, the runtime exception was my fault. I added both the MIDL-generated file for the server (Example1_s.c) AND the file for the client (Example1_c.c) to my project. Apparently the wrong implementation for the remote procedure (Output) must have been executed.

Thanks anyways for helping me.

Now that i've successfully solved my problem you'll get the points.
Have a nice evening! - or what ever your time of day is :)

Featured Post

Free Tool: Postgres Monitoring System

A PHP and Perl based system to collect and display usage statistics from PostgreSQL databases.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction This article is a continuation of the C/C++ Visual Studio Express debugger series. Part 1 provided a quick start guide in using the debugger. Part 2 focused on additional topics in breakpoints. As your assignments become a little more …
Container Orchestration platforms empower organizations to scale their apps at an exceptional rate. This is the reason numerous innovation-driven companies are moving apps to an appropriated datacenter wide platform that empowers them to scale at a …
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…

821 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question