Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> writes:
> Interesting. I wonder why the function is not defined instead with OUT
> parameters.
Because bootstrap mode isn't capable of dealing with array columns,
so you can't define stuff in pg_proc.h that sets up an array of OUT
parameter types. I tried to apply that idea for the pg_locks function
a month or two ago, but it blew up in my face :-(.
It'd be nice to fix this sometime, but not while we are so far past
feature freeze.
regards, tom lane