XL Fortran Enterprise Edition for AIX : User's Guide - IBM

Flushing I/O Buffers
PROGRAM RTEOPTS
USE XLFUTILITY
CALL SETRTEOPTS("err_recovery=no") ! Change setting.
... some I/O statements ...
CALL SETRTEOPTS("err_recovery=yes") ! Change it back.
... some more I/O statements ...
END
Because a user can change these settings through the XLFRTEOPTS environment
variable, be sure to use SETRTEOPTS to set all the run-time options that might
affect the desired operation of the program.
To protect data from being lost if a program ends unexpectedly, you can use the
FLUSH statement or the flush_ subroutine to write any buffered data to a file.
(The FLUSH statement is recommended for better portability.) The following
example shows use of the flush_ subroutine:
USE XLFUTILITY
PARAMETER (UNIT=10)
DO I=1,1000000
WRITE (10,*) I
CALL MIGHT_CRASH
! If the program ends in the middle of the loop, some data
! may be lost.
END DO
DO I=1,1000000
WRITE (10,*) I
CALL FLUSH_(UNIT)
CALL MIGHT_CRASH
! If the program ends in the middle of the loop, all data written
! up to that point will be safely in the file.
END DO
END
Related Information: See “Mixed-Language Input and Output” on page 346 and
the FLUSH statement in the XL Fortran Enterprise Edition for
AIX Language Reference.
Choosing Locations and Names for Input/Output Files
If you need to override the default locations and names for input/output files, you
can use the following methods without making any changes to the source code.
Naming Files That Are Connected with No Explicit Name
To give a specific name to a file that would usually have a name of the form
fort.unit, you must set the run-time option unit_vars and then set an environment
variable with a name of the form XLFUNIT_unit for each scratch file. The
association is between a unit number in the Fortran program and a path name in
the file system.
For example, suppose that the Fortran program contains the following statements:
OPEN (UNIT=1, FORM=’FORMATTED’, ACCESS=’SEQUENTIAL’, RECL=1024)
...
OPEN (UNIT=12, FORM=’UNFORMATTED’, ACCESS=’DIRECT’, RECL=131072)
...
OPEN (UNIT=123, FORM=’UNFORMATTED’, ACCESS=’SEQUENTIAL’, RECL=997)
Implementation Details of XL Fortran Input/Output 331