How do I compile mac osx app developed on 64 bit Mac OSX to run on 32 bit?

I am writing a program in mac osx mountain lion 10.8 in Objective C/C++ . The machine is 64 bit.
I am new to mac world coming from windows .Net development and C/C++

The program has to be compatible with platoform 10.5 mac osx Leopard and onwards both 32bit/64bit.
And the goal is to have single installer/release for 10.5 – 10.8 32bit/64bit

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  • My understanding is (May be I am wrong , please correct me) that If I compile it on 10.8 Lion 64 bit the program will not run on for example on a 10.5 32-bit versions but may run on 10.5 64 bit (ofcourse I have to test it).

    Given my platform 10.8 64 bit can I make xcode compile the app for 32bit/64bit and have one release rather than two variations ?

    On linux/windows if I compile a 32bit program it will run on 64 bit platforms too, but not the other way around I am not sure how xcode/mac can achieve my purpose.

    Solutions Collect From Internet About “How do I compile mac osx app developed on 64 bit Mac OSX to run on 32 bit?”

    Set the Base SDK to Current version of Mac (ex. 10.7)
    Set the Deployment SDK to older version (ex.1.4)

    Change Deployment target as :
    enter image description here

    Change Base SDK as:enter image description here

    Just above this you will find architectures, you can change them to 32 or 64 as your need