Index: src/test1.c
==================================================================
--- src/test1.c
+++ src/test1.c
@@ -4844,10 +4844,33 @@
   }
 
   Tcl_ResetResult(interp);
   return TCL_OK;
 }
+
+/*
+** Usage:  sqlite3_system_errno DB
+**
+** Return the low-level system errno value.
+*/
+static int test_system_errno(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  sqlite3 *db;
+  int iErrno;
+  if( objc!=2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "DB");
+    return TCL_ERROR;
+  }
+  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
+  iErrno = sqlite3_system_errno(db);
+  Tcl_SetObjResult(interp, Tcl_NewIntObj(iErrno));
+  return TCL_OK;
+}
 
 /*
 ** Usage:  sqlite3_db_filename DB DBNAME
 **
 ** Return the name of a file associated with a database.
@@ -7082,10 +7105,11 @@
      { "uses_stmt_journal",             uses_stmt_journal ,0 },
 
      { "sqlite3_release_memory",        test_release_memory,     0},
      { "sqlite3_db_release_memory",     test_db_release_memory,  0},
      { "sqlite3_db_cacheflush",         test_db_cacheflush,      0},
+     { "sqlite3_system_errno",          test_system_errno,       0},
      { "sqlite3_db_filename",           test_db_filename,        0},
      { "sqlite3_db_readonly",           test_db_readonly,        0},
      { "sqlite3_soft_heap_limit",       test_soft_heap_limit,    0},
      { "sqlite3_thread_cleanup",        test_thread_cleanup,     0},
      { "sqlite3_pager_refcounts",       test_pager_refcounts,    0},

Index: test/capi3.test
==================================================================
--- test/capi3.test
+++ test/capi3.test
@@ -170,18 +170,19 @@
 } {SQLITE_OK}
 do_test capi3-3.3 {
   catch {
     set db2 [sqlite3_open /bogus/path/test.db {}]
   }
-  sqlite3_extended_errcode $db2
-} {SQLITE_CANTOPEN}
+  set ::capi3_errno [sqlite3_system_errno $db2]
+  list [sqlite3_extended_errcode $db2] [expr {$::capi3_errno!=0}]
+} {SQLITE_CANTOPEN 1}
 do_test capi3-3.4 {
   sqlite3_errmsg $db2
 } {unable to open database file}
 do_test capi3-3.5 {
-  sqlite3_close $db2
-} {SQLITE_OK}
+  list [sqlite3_system_errno $db2] [sqlite3_close $db2]
+} [list $::capi3_errno SQLITE_OK]
 if {[clang_sanitize_address]==0} {
   do_test capi3-3.6.1-misuse {
     sqlite3_close $db2
   } {SQLITE_MISUSE}
   do_test capi3-3.6.2-misuse {