By selecting certain compile time options, you can make your source code more portable across compilers and platforms.
If you want to improve compatibility with pre-Enterprise PL/I, you could specify the following options:
Note that the option DEFAULT(RETURNS(BYADDR)) will make the invocation of a non-PL/I function on the workstation fail unless the BYVALUE attribute is specified in the RETURNS description.
These (and all the other compiler) options are listed alphabetically in Compile-time option descriptions where they are also described in detail.