Rpv works absolutely different if you compare it with other tools to design and manage reports. Rpv is a tool which is able to 'understand' simple plain text files, which you can generate using your favorite language and to format them using the graphical capabilities of Windows. These files that you (your program) will generate, will follow a very easy syntax to Rpv understands them properly and to format the text successfully. Once that you or your program has finished the file, just run Rpv from your program to preview or print the file.
Since Rpv reads text files (*.rpv are text files), Rpv is one of the best choices to any programming language running on Windows, Dos or even Unix because a plain text file can be generated using any language and any operating system. It is not required to know an additional programming language to extract your data from your databases.