AW: [HACKERS] varchar() vs char16 performance

I had thought that char2-16 add _no_ functionality over the char() and
varchar() types; Tatsuo points out at least one capability which they
have. Are there any others?

They give and take a char * pointer to a C function like
create function upper(char16)
returning char16 as '/u/my/upper.so' language 'sql';
whereas char() gives a varlena pointer.

Andreas