I found the following useful - just a way of using PQgetisnull from

libpq++.

Patrick Welche

src/interfaces/libpq++/pgdatabase.cc

@@ -10,7 +10,7 @@
  * Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/interfaces/libpq++/Attic/pgdatabase.cc,v 1.3 1999/06/05 18:05:17 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/interfaces/libpq++/Attic/pgdatabase.cc,v 1.4 1999/09/21 21:19:31 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -115,6 +115,18 @@ return PQgetvalue(pgResult, tup_num, FieldNum(field_name));
 }
 
 
+int PgDatabase::GetIsNull(int tup_num, int field_num)
+{ 
+return PQgetisnull(pgResult, tup_num, field_num); 
+}
+
+
+int PgDatabase::GetIsNull(int tup_num, const char* field_name)
+{ 
+return PQgetisnull(pgResult, tup_num, FieldNum(field_name)); 
+}
+
+
 int PgDatabase::GetLength(int tup_num, int field_num)
 { 
 return PQgetlength(pgResult, tup_num, field_num); 
@@ -126,6 +138,7 @@ int PgDatabase::GetLength(int tup_num, const char* field_name)
 return PQgetlength(pgResult, tup_num, FieldNum(field_name)); 
 }
 
+
 int PgDatabase::GetLine(char* string, int length)
 { 
 return PQgetline(pgConn, string, length); 

src/interfaces/libpq++/pgdatabase.h

@@ -13,7 +13,7 @@
  * Copyright (c) 1994, Regents of the University of California
  *
  *
- *  $Id: pgdatabase.h,v 1.2 1999/05/23 01:04:01 momjian Exp $
+ *  $Id: pgdatabase.h,v 1.3 1999/09/21 21:19:31 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,6 +48,8 @@ public:
   short FieldSize(const char* field_name);
   const char* GetValue(int tup_num, int field_num);
   const char* GetValue(int tup_num, const char* field_name);
+  int GetIsNull(int tup_num, int field_num);
+  int GetIsNull(int tup_num, const char* field_name);
   int GetLength(int tup_num, int field_num);
   int GetLength(int tup_num, const char* field_name);
   void DisplayTuples(FILE *out = 0, int fillAlign = 1,