I am writing a COM function that will take a string in and return a modified string back. This COM code is written in C++ and will only be used in a C++ environment, meaning is does not need to be used by any other language (VB). My question is, what is the best (easiest to handle) string type to use for this? LPSTR? BSTR? The output string might copy the input string, and then append another string to the output.