getting stderr from an app launched via execv

I have an application that calls another app and reads its output from stdout and also traps output to stderr too.

It originally used popen and trapped stderr by passing "2>out.err" as the last parameter and it worked fine.
But I also needed to be able to send a SIGINT to the program and couldn't using the popen architecture.

So I've changed my code to use fork / execv and now the last parm "2>out.err" is being passed to the app and not treated the same was as it was with popen.

So my question is, how can I trap prints to stderr from the app that I launched using execv?

Thanks
Kevin

In the child process, just before you exec...

- open "out.err" for writing
- close descriptor 2
- Call dup with the descriptor from step 1