That is another possibility, and made me think of the following hackish solution that does what the original code was meant to: 
system("yes yes | cleartool setcs $CS_FILENAME 2> /dev/null");

[download]
(This assumes Unix.)

If you want more flexible error handling you need to go down the other paths I suggested.

In reply to Re^2: IPC::open3 obfuscification by tilly
in thread IPC::open3 obfuscification by Anonymous Monk

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