Attaching to a Running Process

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G.13.2.2 Attaching to a Running Process

With GDB it is always possible to debug a running process by attaching to it. It is possible to debug a DLL this way. The limitation of this approach is that the DLL must run long enough to perform the attach operation. It may be useful for instance to insert a time wasting loop in the code of the DLL to meet this criterion.

Launch the main program main.exe.
```
          $ main
```
Use the Windows Task Manager to find the process ID. Let's say that the process PID for main.exe is 208.
Launch gdb.
```
          $ gdb
```
Attach to the running process to be debugged.
```
          (gdb) attach 208
```
Load the process debugging information.
```
          (gdb) symbol-file main.exe
```
Break somewhere in the DLL.
```
          (gdb) break ada_dll
```
Continue process execution.
```
          (gdb) cont
```

This last step will resume the process execution, and stop at the breakpoint we have set. From there you can use the standard approach to debug a program as described in (see Running and Debugging Ada Programs).