Writing to IFS from RPGLE but needs UTF-8

I need to create a file in the IFS and the file HAS to be encoded in UTF-8
(CCSID 1208).

The machine is unfortunately running on V7R1 and that is due to a software
package that cannot (as I am told be migrated to more current releases). So
writing with SQL is out of the equation, sadly.



I have tested a function based on Scott Klements writings and while it works
with conversion to ASCII it fails when I change to CCSID 1208.



As per the example the IFS file is first created with 1208 as the CCSID.
This works and is coded thus:



c eval fd = open('/home/ao/ch5_file3.txt':

c O_CREAT+O_WRONLY+O_CCSID:

c S_IWUSR+S_IRUSR+S_IRGRP+S_IROTH:

c 1208)



But when the file is closed an reopened this open gets an error:



c eval fd = open('/home/ao/ch5_file3.txt':

c O_WRONLY+O_TEXTDATA)



I receive an "open() conversion error"



Any suggestions? I assume that I need some other parameters for the second
open when using UTF-8 but I have as yet not found which one to use or
possibly omit.