Many systems provide a pseudo-statement called INCLUDE (or sometimes INSERT which inserts the entire contents of a separate text file into the source code in place of the INCLUDE statement. This feature can be particularly useful when the same set of statements, usually specification statements, has to be used in several different program units. Such is often the case when defining a set of constants using PARAMETER statements, or when declaring common blocks with a set of COMMON statements. INCLUDE statements reduce the key-punching effort and the risk of error. Although non-standard, INCLUDE statements do not seriously compromise portability because they merely manipulate the source files and do not alter the source code which the compiler translates.