Suppose I want to build a C++ program that can manipulate another program's data. My program knows where this data is located and what kind of data it's supposed to be dealing with (int, string, etc.). How do I tell my program to access and change this data? ---------- I think I found my answer: http://stackoverflow.com/questions/6016156/accessing-memory-of-other-applications-c I'll have to use an API that OS X Yosemite supports; given Apple's obsession with security, I doubt any such API exists. Edit: Another answerer says I could also try launching the program in question from within my program.