A command block that starts with a BEGIN-BLOCK command and ends with a END-BLOCK command (also called a BEGIN block, see "BEGIN-BLOCK Initiate command block ") can be used within the procedure as a subprocedure. Such a procedure is called with the INCLUDE-BLOCK command (see "INCLUDE-BLOCK Executing a BEGIN block as a subprocedure "). The execution of the procedure jumps to the command line that starts with the specified tag and that contains the corresponding BEGIN-BLOCK command. After processing the BEGIN block, the procedure continues with the command that follows the INCLUDE-BLOCK command.
Subprocedures are used in a manner similar to that of subroutines in higher level programming languages. They promote clarity and make the procedure easier to maintain and update. The calls for such procedures execute faster than the calls for external procedures in which an additional procedure container must first be opened.