If you set the MS Compiler directive, the LOCKING clause in the SELECT statement is supported. 
               
            
 
            
            General Format 
               
            
 
            
             
               	 

 
               
            
 
            
            General Rules 
               
            
 
            
             
               	 
               - For SEQUENTIAL and LINE SEQUENTIAL files only EXCLUSIVE locking is allowed. 
                  	 
               
- If MANUAL is specified multiple locks can be applied to the file. 
                  	 
               
- If AUTOMATIC is specified a single lock is applied automatically to the current record. 
                  	 
               
- For SEQUENTIAL and LINE SEQUENTIAL files the default LOCKING mode is EXCLUSIVE. 
                  	 
               
- For RELATIVE and INDEXED files the default LOCKING mode is AUTOMATIC. 
                  	 
               
- If the MANUAL option is specified the UNLOCK statement will release all locks.