How to attach VC++ debugger (or gdb) in this situation?

Question

I'm running a typical producer and consumer process, but they are executed by using pipe in the command line like the following:

c:\>producer | consumer

producer is just printing out data to stdout, and consumer reads from stdin.

My problem is that I want to debug consumer process. What is the best way to do it in both VC++ and gdb?

One solution is dumping out into a file and reading the file:

c:\>producer > temp.data
c:\>consumer < temp.data

However, the amount of data communicated by the two is extremely large. temp.data would be more than 1TB! I may use compression, but it takes huge amount of time for just compressing/uncompressing. So, I want to do it online.

Current my workaround is:

1. Put a sleep function (e.g., sleeping 10 seconds) in the main function of consumer before doing any job such as reading from stdin.
2. Invoke producer | consumer from the console. Then, consumer is started with a 10-second-sleep.
3. Attach consumer process by VC++ and gdb in 10 seconds.
4. Okay, after the sleep, I can now debug the consumer.

Yes, this workaround is working. But, it's pretty annoying. I guess there is a better way to debug in this situation. I appreciate any idea for it.

Answer 1

Two solutions come to mind

Change your sleep to be

// this waits indefinitely without killing the CPU
while(true) {SleepEx(100, FALSE);} 

Once you attach the debugee manually you just put a break point on the sleep and then you can jump out of the loop manually.

or better yet (unless its a service/process with no UI access) add a DebugBreak statement where the Sleep is instead. This will cause the an exception to be thrown and you will be prompted to kill the process or debug launching your default debugger on the system..

DebugBreak();