Apparently in PosgreSQL 7.2.3 (the Redhat 7.3 version, which has some
patching involved), pg_detoast_datum is defined in fmgr backend code,
but this function is not defined anywhere in any library, especially not
libpq. It is the necessity to use fmgr.h functions that brings about the
need to have pg_detoast_datum. The V1 interface itself requires fmgr.h,
this is where PG_FUNCTION_INFO_V1 is declared, along with other V1
macros. My guess is that pg_detoast_datum should be in a library
somewhere, but manually compiling PostgreSQL 7.2.3 source with
unstripped libraries shows that no dynamic library produced from the
source build contains the necessary functions. There does not appear to
be any libfmgr.so (of any version), unless there is some configure
option I am missing.
How do I get around this without using non-Redhat packages and without
forcing users to install another version of PostgreSQL? At this point it
looks like there is no choice but to use the V0 interface to libpq and
develop separate projects for other versions of linux PostgreSQL that
have more recent versions.
D. Stimits