Inspired by Safari Books Online’s new multi boom search, but not wishing to pay the $39 USD / month fee (https://www.safaribooksonline.com/) I tried various apps to achieve the same on my library of PDF books, most of which purchased from O’Reilly’s eBook store (http://shop.oreilly.com/).
I tried the common ones iAnnotate, PDFExpert, GoodReader, but while some had multi book search on contents, the search results didn’t show where in the book the result was found, just which books had the search term.
Enter PDF PRO 2, which is the only app in the App Store as of August 2014 that gives this functionality. I will leave the picture to do the talking:
App Store link: https://itunes.apple.com/gb/app/pdf-pro-2-the-ultimate-pdf-app/id741293420?mt=8