The function name is:
UERRORCODE jdeFromUnicode(ZCHAR *dest, const JCHAR *src, int targetCapacity, const JCHAR *enc);
dest = pointer to a destination buffer
src = pointer to the source JCHAR
targetCapacity = the size of the destination buffer
enc = encoding target codepage. See jdeUnicode.h for supported codepages
In order to find out the size of the required output buffer, you can use the following function:
unsigned int jdeStrLen(const JCHAR *s);
Which will give you the number of chars found in the string.
There are other functions available. There is a very good manual written on the subject that you can download from the peoplesoft website. The title is : ERP Unicode Conversion Guidelines.
There is also a "system API documentation" in compiled HTML format. I wonder if a newer version was created for ERP8.9 and Unicode support as well...