On Windows, how do I get my app to tell another app to open a file that I just generated. For example, "WordPad, please open 'foo.rtf' that I just made." Or Word, or other big apps that may already be open with other files. I have to assume that the app may or may not be open already.
Alternatively, if I could only do the equivalent of double-clicking the file, so as to open it with its default application, that would still be all right.