Method and apparatus for software technology injection for operating systems which assign separate process address spaces

A machine readable storage having stored thereon a computer program for enhancing the operable functionality of an existing target software application with a complex technological add-in, the computer program comprising a routine set of instruction for causing the machine to perform the steps of:

• mapping a library function containing a surrogate procedure to at least one of a plurality of application programs executing in a computer system, said at least one application program including the existing target software application;
• upon command from an injection software application program, selectively causing only said library function mapped to the existing target software application to replace a first pointer in memory to a target procedure for the existing target software application with a second pointer to said surrogate procedure, so that said surrogate procedure receives intercepted messages that would otherwise be received by said target procedure;
• processing said intercepted messages in said surrogate procedure to modify an operating feature of said target application program;
• and,
• calling an emulation procedure separate from and external to said surrogate procedure to assist said surrogate procedure in processing said intercepted messages by performing complex processing to enhance the operable functionality of the existing target software application.