11.3. Compiling for a Target Runtime Environment
In designing applications, you may or may not know what kind of system will run them. On HP-UX systems, you can use specific compiler options to indicate a specific machine architecture, data model, or operating system revision where the resulting application will run. The particular options used in specifying the machine architecture are +DA, +DD, +DS, and +DO.
The +DA option lets you specify the instruction set architecture that should be used. It is important to set this option correctly, since code compiled for a later architecture will not execute on earlier architectures. Different levels generate different magic numbers in the a.out file. As a rule, you should choose the lowest ...