Allow binary I/O of type "void".

void_send is useful for the same reason that void_out doesn't throw error,
namely that someone might do "select void_returning_func(...)"  from a
client that prefers to operate in binary mode.  The void_recv function may
or may not have any practical use, but we provide it for symmetry.

Radosław Smogura

src/backend/utils/adt/pseudotypes.c

@@ -212,6 +212,34 @@ void_out(PG_FUNCTION_ARGS)
 	PG_RETURN_CSTRING(pstrdup(""));
 }
 
+/*
+ * void_recv	- binary input routine for pseudo-type VOID.
+ *
+ * Note that since we consume no bytes, an attempt to send anything but
+ * an empty string will result in an "invalid message format" error.
+ */
+Datum
+void_recv(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_VOID();
+}
+
+/*
+ * void_send	- binary output routine for pseudo-type VOID.
+ *
+ * We allow this so that "SELECT function_returning_void(...)" works
+ * even when binary output is requested.
+ */
+Datum
+void_send(PG_FUNCTION_ARGS)
+{
+	StringInfoData buf;
+
+	/* send an empty string */
+	pq_begintypsend(&buf);
+	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
+}
+
 
 /*
  * trigger_in		- input routine for pseudo-type TRIGGER.

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201102191
+#define CATALOG_VERSION_NO	201102221
 
 #endif

src/include/catalog/pg_proc.h

@@ -4226,6 +4226,10 @@ DATA(insert OID = 2502 (  anyarray_recv		   PGNSP PGUID 12 1 0 0 f f f t f s 1 0
 DESCR("I/O");
 DATA(insert OID = 2503 (  anyarray_send		   PGNSP PGUID 12 1 0 0 f f f t f s 1 0 17 "2277" _null_ _null_ _null_ _null_	anyarray_send _null_ _null_ _null_ ));
 DESCR("I/O");
+DATA(insert OID = 3120 (  void_recv			   PGNSP PGUID 12 1 0 0 f f f t f i 1 0 2278 "2281" _null_ _null_ _null_ _null_ void_recv _null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3121 (  void_send			   PGNSP PGUID 12 1 0 0 f f f t f i 1 0 17 "2278" _null_ _null_ _null_ _null_	void_send _null_ _null_ _null_ ));
+DESCR("I/O");
 
 /* System-view support functions with pretty-print option */
 DATA(insert OID = 2504 (  pg_get_ruledef	   PGNSP PGUID 12 1 0 0 f f f t f s 2 0 25 "26 16" _null_ _null_ _null_ _null_	pg_get_ruledef_ext _null_ _null_ _null_ ));

src/include/catalog/pg_type.h

@@ -615,7 +615,7 @@ DATA(insert OID = 2276 ( any			PGNSP PGUID  4 t p P f t \054 0 0 0 any_in any_ou
 #define ANYOID			2276
 DATA(insert OID = 2277 ( anyarray		PGNSP PGUID -1 f p P f t \054 0 0 0 anyarray_in anyarray_out anyarray_recv anyarray_send - - - d x f 0 -1 0 0 _null_ _null_ ));
 #define ANYARRAYOID		2277
-DATA(insert OID = 2278 ( void			PGNSP PGUID  4 t p P f t \054 0 0 0 void_in void_out - - - - - i p f 0 -1 0 0 _null_ _null_ ));
+DATA(insert OID = 2278 ( void			PGNSP PGUID  4 t p P f t \054 0 0 0 void_in void_out void_recv void_send - - - i p f 0 -1 0 0 _null_ _null_ ));
 #define VOIDOID			2278
 DATA(insert OID = 2279 ( trigger		PGNSP PGUID  4 t p P f t \054 0 0 0 trigger_in trigger_out - - - - - i p f 0 -1 0 0 _null_ _null_ ));
 #define TRIGGEROID		2279

src/include/utils/builtins.h

@@ -504,6 +504,8 @@ extern Datum anyenum_in(PG_FUNCTION_ARGS);
 extern Datum anyenum_out(PG_FUNCTION_ARGS);
 extern Datum void_in(PG_FUNCTION_ARGS);
 extern Datum void_out(PG_FUNCTION_ARGS);
+extern Datum void_recv(PG_FUNCTION_ARGS);
+extern Datum void_send(PG_FUNCTION_ARGS);
 extern Datum trigger_in(PG_FUNCTION_ARGS);
 extern Datum trigger_out(PG_FUNCTION_ARGS);
 extern Datum language_handler_in(PG_FUNCTION_ARGS);