INPUT Phrase (Sequential Files)
The file is opened for input operations. The file position indicator is set to the first record in the file. If no records exist in the file, the file position indicator is set so that processing of the first sequential READ statement results in an AT END condition.
If SELECT OPTIONAL is specified in the file-control entry, OPEN statement processing causes the program to check for the presence or absence of this file at run time. If the file is absent, the first READ statement for this file causes the AT END condition to occur.
Under the OPTION(*NOBLK) option, the compiler generates code to block output records and unblock input
records if the following conditions are satisfied:
- The file access is sequential.
- The organization of the file is sequential and the file is open only for input or output.
- The file is assigned to DISK, DATABASE, DISKETTE, or TAPEFILE.
The BLOCK CONTAINS clause does not control the blocking factor for any files except tape files. The BLOCK CONTAINS clause controls the blocking factor for all files.