HP 3000 Manuals HP 3000 Manuals
The OPEN Statement Files are always referenced in FORTRAN 77 programs using unit numbers. Under MPE/iX, FORTRAN 77 preconnects two units at the beginning of every program. Unit five is connected to $STDIN by the formal file designator FTN05 and unit six is connected to $STDLIST by the formal file designator FTN06. If a file equation is present for either FTN05 or FTN06, the temporary and permanent file domains are searched before a new file is created. An OPEN statement is not required to perform I/O with units five and six. Units five and six can be reassigned using the OPEN statement at any time. The OPEN statement connects MPE/iX files to FORTRAN unit numbers. If present, the FILE clause in the OPEN statement must specify a legal MPE/iX file name that is connected to the specified unit. If the status clause on the OPEN statement specifies SCRATCH, FORTRAN 77 creates an MPE/iX nameless file and deletes it when the file is closed. An OPEN status of UNKNOWN causes FORTRAN to open or create the file indicated by the FILE clause, or if no FILE clause is present, to create an MPE/iX nameless file. All files created by FORTRAN are created as MPE/iX "NEW" and are saved unless the DELETE option appears in the CLOSE statement (except SCRATCH files, which are always deleted). FORTRAN 77 creates files of type BINARY if the FORM clause specifies UNFORMATTED, otherwise it creates files of type ASCII. The RECL parameter in the OPEN statement always specifies byte length, not word length as is sometimes used in MPE/iX.