1. A method for performing runtime checking operations in a compiled programming development environment, comprising the steps of: a) compiling a source code file into executable object code comprising machine language instructions, wherein said source code file includes aggregate data items and pointers and also includes expressions which manipulate said aggregate data items and pointers, wherein said step of compiling comprises: creating data structures for aggregate data items and pointers in the source code file; and inserting calls to runtime checking functions for one or more expressions in the source code file which manipulate said aggregate data items and pointers; and b) executing the executable object code, wherein said step of executing comprises: executing one or more of said runtime checking functions to determine if invalid operations occur in said expressions which manipulate said aggregate data items and pointers; and reporting an error to the user if an invalid operation is found to occur after said step of executing one or more of said runtime checking functions.