How to get the return code from a batch/shell script that launched from C++ code

How to get the return code from a batch/shell script that launched from
C++ code

We have a C++ program, sometimes this program need to execute a user
defined batch/shell/ant script. We are not able to control how this script
runs. Is there a way to get the return code from C++ program?
Something like: exec a script.sh > status.tmp ?
We need to support both Windows and Linux.
Any ideas?