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

I/O Redirection
The important things to note are:
▌1▐ The behavior of the xlf90, xlf90_r, xlf90_r7, xlf95, xlf95_r, and xlf95_r7
commands when you do not specify an option is different from XL Fortran
Version 2.3 in this case. The Fortran 90 and Fortran 95 standards require this
behavior. To minimize migration problems, the xlf, xlf_r, xlf_r7, f77, and fort77
commands keep the same default as XL Fortran Version 2.3 and append to the
end of the file.
Attention: If your program depends on the old behavior to append to the end
of an existing file with STATUS=’OLD’, you need to use the option
-qposition=appendold or POSITION= specifiers when making the switch to
the xlf90, xlf90_r, xlf90_r7, xlf95, xlf95_r, or xlf95_r7 command. Otherwise,
when you compile the program with these commands and run it, the new data
will overwrite the file instead of appending to it.
▌2▐ -qposition=appendold produces the default XL Fortran Version 2.3
behavior for positioning the file pointer. This option is in the configuration-file
stanza for the xlf, xlf_r, xlf_r7, f77, and fort77 commands but is not in the
configuration-file stanza for the xlf90, xlf90_r, xlf90_r7, xlf95, xlf95_r, and
xlf95_r7 commands.
▌3▐ This file position was not possible in XL Fortran Version 2.3.
Preserving the XL Fortran Version 2.3 File Positioning
If you are upgrading from XL Fortran Version 2.3 and want the file positioning to
work the same way as before, note the following guidelines:
v
v
As long as you continue to use the xlf_r, xlf_r7, xlf, f77, and fort77 commands,
you do not need to make any changes.
When you make the transition to the xlf90, xlf90_r, xlf90_r7, xlf95, xlf95_r, and
xlf95_r7 commands:
– Add -qposition=appendold for programs that were previously compiled
without any -qposition option.
– Add -qposition=appendold:appendunknown for programs that were
previously compiled with -qposition=append.
You can use the redirection operator on the command line to redirect input to and
output from your XL Fortran program. How you specify and use this operator
depends on which shell you are running. Here is a ksh example:
328 XL Fortran Enterprise Edition for AIX : User’s Guide