diff --git a/src/ivfflat.c b/src/ivfflat.c
index 62a4ea2..3753a74 100644
--- a/src/ivfflat.c
+++ b/src/ivfflat.c
@@ -20,7 +20,7 @@ static relopt_kind ivfflat_relopt_kind;
  * Initialize index options and variables
  */
 void
-_PG_init(void)
+IvfflatInit(void)
 {
 	ivfflat_relopt_kind = add_reloption_kind();
 	add_int_reloption(ivfflat_relopt_kind, "lists", "Number of inverted lists",
diff --git a/src/ivfflat.h b/src/ivfflat.h
index 92912c9..0e0e6f4 100644
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -84,9 +84,6 @@
 /* Variables */
 extern int	ivfflat_probes;
 
-/* Exported functions */
-PGDLLEXPORT void _PG_init(void);
-
 typedef struct VectorArrayData
 {
 	int			length;
@@ -288,6 +285,7 @@ void		IvfflatAppendPage(Relation index, Buffer *buf, Page *page, GenericXLogStat
 Buffer		IvfflatNewBuffer(Relation index, ForkNumber forkNum);
 void		IvfflatInitPage(Buffer buf, Page page);
 void		IvfflatInitRegisterPage(Relation index, Buffer *buf, Page *page, GenericXLogState **state);
+void		IvfflatInit(void);
 PGDLLEXPORT void IvfflatParallelBuildMain(dsm_segment *seg, shm_toc *toc);
 
 /* Index access methods */
diff --git a/src/vector.c b/src/vector.c
index e9a151e..e76d43f 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -2,7 +2,9 @@
 
 #include <math.h>
 
+#include "ivfflat.h"
 #include "vector.h"
+
 #include "fmgr.h"
 #include "catalog/pg_type.h"
 #include "lib/stringinfo.h"
@@ -29,6 +31,15 @@
 
 PG_MODULE_MAGIC;
 
+/*
+ * Initialize index options and variables
+ */
+void
+_PG_init(void)
+{
+	IvfflatInit();
+}
+
 /*
  * Ensure same dimensions
  */
diff --git a/src/vector.h b/src/vector.h
index 93aeb6a..292be98 100644
--- a/src/vector.h
+++ b/src/vector.h
@@ -14,6 +14,9 @@
 #define PG_GETARG_VECTOR_P(x)	DatumGetVector(PG_GETARG_DATUM(x))
 #define PG_RETURN_VECTOR_P(x)	PG_RETURN_POINTER(x)
 
+/* Exported functions */
+PGDLLEXPORT void _PG_init(void);
+
 typedef struct Vector
 {
 	int32		vl_len_;		/* varlena header (do not touch directly!) */