, I found that if both read_proc and for_proc are used together, for_proc will run and then read_proc will hang. If I comment either out, then the program will run properly. This behavior is under ActivePerl. I tried it under UNIX Perl out of curiousity, and it works properly. Both are the same version of Perl and the same version of Benchmark.
Perhaps we've discovered a bug in ActivePerl? is there some other explaination for this behavior?