Question

Today I ran into a problem were I needed to remote-debug a program. The program was launched from another system, so I really don’t have an opportunity to interact with it on the command line. I could change its source easily though.

What I needed to happen was for the program to start normally, and then wait for me to attach to it with a debugger. I couldn’t come up with a way to do it that made me happy. I did find the bug, but without the help of the debugger.

while(true) { } 

Kept the process alive, and then I could ‘set next statement’ with the debugger, but it seemed awkward and rude.

Console.ReadLine(); 

Seemed odd to type since there wasn’t actually a Console for me to press enter at. (It didn’t work, either. Set next statement and then run takes you back into the ReadLine() wait.)

So what kind of code can I insert into a .NET/CLR/C# program that says ‘wait here until I can attach with a debugger’?

Answer 1

You can use the System.Diagnostics.Debugger.IsAttached property to check if a debugger is attached to the process. This application will wait until a debugger has been attached:

using System; using System.Diagnostics; using System.Threading;  namespace DebugApp {     class Program     {         static void Main(string[] args)         {             Console.WriteLine('Waiting for debugger to attach');             while (!Debugger.IsAttached)             {                 Thread.Sleep(100);             }             Console.WriteLine('Debugger attached');         }     } }