diff --git a/dbdimp.c b/dbdimp.c
index 9a2a49c..381cae2 100644
--- a/dbdimp.c
+++ b/dbdimp.c
@@ -1192,8 +1192,9 @@ sqlite3_db_create_aggregate(pTHX_ SV *dbh, const char *name, int argc, SV *aggr_
 
 
 int
-sqlite_db_collation_dispatcher(SV *func, int len1, const void *string1,
-                                         int len2, const void *string2)
+sqlite_db_collation_dispatcher(
+  void *func, int len1, const void *string1,
+              int len2, const void *string2)
 {
     dTHX;
     dSP;
@@ -1223,8 +1224,8 @@ sqlite_db_collation_dispatcher(SV *func, int len1, const void *string1,
 
 int
 sqlite_db_collation_dispatcher_utf8(
-  SV *func, int len1, const void *string1,
-            int len2, const void *string2)
+  void *func, int len1, const void *string1,
+              int len2, const void *string2)
 {
     dTHX;
     dSP;
@@ -1299,7 +1300,7 @@ sqlite3_db_create_collation(pTHX_ SV *dbh, const char *name, SV *func )
 }
 
 int
-sqlite_db_progress_handler_dispatcher( SV *handler )
+sqlite_db_progress_handler_dispatcher( void *handler )
 {
     dTHX;
     dSP;