The enclave defines the scope of language semantics

By definition, the scope of a language statement is that portion of code in which it has semantic effect. The enclave defines the scope of the language semantics for its component routines, just as a COBOL run unit defines the scope of semantics of a COBOL program. Scope encompasses names, external data sharing, and control statements such as C's exit(), COBOL's STOP RUN, Fortran’s STOP, and PL/I's STOP and EXIT statements.