Release 10.1A: OpenEdge Development:
Debugging and Troubleshooting

Attachable mode

When you first start the Debugger and then attach it to a running client process, the Debugger runs in attachable mode. The client can be any 4GL client, WebSpeed agent, or AppServer running on the same machine or on the same LAN as the Debugger. The Debugger gets control immediately upon attaching to the process. Once attached, the Debugger works the same as in application mode; that is, you are debugging an already running application.

By running the Debugger in attachable mode you can debug:

A previously started session.
A session on another machine.
The AppServer, WebSpeed, asynchronous AppServer procedures, OpenClient, and Web Services directly from the Debugger without adding statements to the source code to start the Debugger.

To successfully attach the Debugger, the process you attach to must be in a debug-ready state. For more information, see the "Making the process ready for debugging" section.

Running an attachable mode debugging session has both security and performance considerations. The Debugger and the 4GL interpreter communicate by opening a socket on a port and establishing a connection. In attachable mode, the interpreter has to open a socket on a known port and wait for a connection from the Debugger. The open connection introduces a potential security gap and a performance degradation. To close the security gap, OpenEdge requires that you have physical or login access to the local machine to make a process debug-ready. To avoid the performance hit of unnecessary polling, you can make the process debug-ready by opening the connection only when you are ready to debug the process.