You might take a look at:

This takes the same approach, but used a batch file rather than ShellExecuteEx:
https://www.appeon.com/developers/get-help/knowledgebase/powerbuilder-printing-pdfs-using-acrobat-reader.html

This lists a number of other options:
https://community.appeon.com/index.php/qna/q-a/pdf-documents-print-option

We use the shellexecute approach, as you do.  As you may have noticed, Adobe leaves an empty minimized reader around after you do a print.  That's why the solution first link above kills the Adobe Process when the print is completed.

Hi Tracy;

  Not currently - only in the Web Browser control which has a PrintAsPDF() method. However neither the DW Control or the DataStore control has this method support currently. This would require an enhancement to the DS/DC Native PDF feature.

  However, you can do this with external tool;s (ie: Ayumini) but, these would require an extra purchase & programming.

Regards .. Chris

You can still use the IE browser control. You have to have Adobe installed in order to view a PDF. My code example has a function of_execwb_print that can be used to print.

https://www.topwizprogramming.com/freecode_webbrowser.html

Can you check this thread 

https://community.appeon.com/index.php/qna/q-a/print-pdf-files-from-folder-in-powerbuilder-application#reply-27375

Happiness Always
BKR Sivaprakash

Looks like the problem my beta tester has is that last time he used Acrobat Reader, he printed to pdf instead of printing to a printer.  Acrobat somehow remembers the last Print option used. When printing from my app, Acrobat will ask where to print the file...