Re: Should contrib modules install .h files?

>>>>> "Peter" == Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:

>> A review of contrib/ suggested that cube, hstore, isn, ltree and seg
>> were the only modules that had useful headers to install, so do
>> those.

Peter> I'm missing some guidance what an extension using those headers
Peter> is supposed to do. How does it get the right -I options?

All of the below assumes PGXS.

If your extension is relying on pg11+, or you have checked the pg
version when constructing the makefile, you can just do:

PG_CPPFLAGS += -I$(includedir_server)/extension/hstore

and #include "hstore.h" will work.

If you need to workaround for old versions in one makefile, as I do,
then you can do something along these lines (this goes before the
include $(PGXS) line):

# MAJORVERSION and includedir_server are not defined yet, but will be
# defined before PG_CPPFLAGS is expanded. So we use conditional
# expansions rather than 'ifeq' syntax.

# for pg11+, hstore.h will be installed here
HSTORE_INCDIR = $(includedir_server)/extension/hstore

# for pg 9.5/9.6/10, we have a local copy of hstore.h since it happens
# to be the same, barring non-semantic whitespace, between the three
# versions
HSTORE_INCDIR_OLD = old_inc

PG_CPPFLAGS += -I$(HSTORE_INCDIR$(if $(filter 9.% 10,$(MAJORVERSION)),_OLD))

If you need to distinguish more versions for whatever reason you can do
this:

HSTORE_INCDIR = $(includedir_server)/extension/hstore
HSTORE_INCDIR_10 = whatever
HSTORE_INCDIR_9.6 = whatever
HSTORE_INCDIR_9.5 = whatever
HSTORE_INCDIR_9.4 = whatever
HSTORE_INCDIR_9.3 = whatever
PG_CPPFLAGS += -I$(HSTORE_INCDIR$(if $(filter 9.% 10,$(MAJORVERSION)),_$(MAJORVERSION)))

--
Andrew (irc:RhodiumToad)