SAP关于START-OF-SELECTION的说明
Statements that are not assigned to a processing block are never executed. An exception to this are any non-declarative statements between the REPORT or PROGRAM statement and the first processing block, which are assigned to the default event
START-OF-SELECTION if a program does not contain an explicit START-OF-SELECTION block, these statements form the entire START-OF-SELECTION block. If a START-OF-SELECTION keyword is already included in your program, these statements are inserted at the beginning of this block. If the program does not contain any explicit event blocks, all non-declarative statements are assigned to the default processing block START-OF-SELECTION.
下面给出我对这段话的理解：
也就是说，不归属于任何processing block的语句都不会被执行。不过有个例外，就是在REPORT或PROGRAM与第一个processing block之间的任何非声明性语句，都会被分配给默认的事件START-OF-SELECTION。如果一个程序中不存在显式的START-OF-SELECTION模块（即程序中不存在关键字START-OF-SELECTION），则这些非声明性语句就构成整个START-OF-SELECTION块；如果程序中含有关键字START-OF-SELECTION的话，则这些非声明性语句会被插入START-OF-SELECTION模块的起始处。如果程序中不存在任何显式的事件块，则所有非声明性语句都会被分配给默认的事件块START-OF-SELECTION。