Thank you very, very much so far.
>This is the intended and documented behavior --- see fmgr/README:
>: The DirectFunctionCallN routines will not bother to fill in
>: fcinfo->flinfo (indeed cannot, since they have no idea about an OID for
>: the target function); they will just set it NULL.
I actually read this text, but somehow did not consider it as solution to my
problem.
I think, I'll have a closer look at the involved structures as well as the
system of calling existing functions now.
I'd be glad, if you assist me with further emerging problems in the future
;)
kind regards, Jessica