Get rid of libpq-fe.h inclusion in public headers

The problem with libpq-fe.h is that it is installed in unpredictable
places on different platforms. As a result, a user that uses ODB with
PostgreSQL (and who doesn't really know or care about libpq) is forced
to make sure their application is able to find and include libpq-fe.h
correctly.

Luckily for us, we only use a handful of libpq pointers in public
headers and the workaround is to forward declare them and use that
instead of including libpq-fe.h (which is instead included in source
files).

1 files changed, 21 insertions, 0 deletions

diff --git a/odb/pgsql/pgsql-fwd.hxx b/odb/pgsql/pgsql-fwd.hxx
new file mode 100644
index 0000000..45f085d
--- /dev/null
+++ b/odb/pgsql/pgsql-fwd.hxx
@@ -0,0 +1,21 @@
+// file      : odb/pgsql/pgsql-fwd.hxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : Copyright (c) 2005-2011 Code Synthesis Tools CC
+// license   : GNU GPL v2; see accompanying LICENSE file
+
+#ifndef ODB_PGSQL_PGSQL_FWD_HXX
+#define ODB_PGSQL_PGSQL_FWD_HXX
+
+#include <odb/pre.hxx>
+
+// Forward declaration for some of the types defined in libpq-fe.h. This
+// allows us to avoid having to include libpq-fe.h in public headers.
+//
+typedef unsigned int Oid;
+
+typedef struct pg_conn PGconn;
+typedef struct pg_result PGresult;
+
+#include <odb/post.hxx>
+
+#endif // ODB_PGSQL_PGSQL_FWD_HXX