the primary measurement of software is size, specifically functional size. the generic principles of functional size are described in the iso/iec 14143<ref name="iso/iec 14143"></ref>. software size is principally measured in function points. it can also be measured in lines of code, or specifically, source lines of code (sloc) which is functional code excluding comments. whilst measuring sloc is interesting, it is more an indication of effort than functionality. two developers could approach a functional challenge using different techniques, and one might need only write a few lines of code, and the other might need to write many times more lines to achieve the same functionality. the most reliable method for measuring software size is code agnostic, from the user's point of view - in function points.