More.

sqlite.go

@@ -37,7 +37,7 @@ var instance struct {
 
 func compileSQLite() {
 	if RuntimeConfig == nil {
-		RuntimeConfig = wazero.NewRuntimeConfig().WithMemoryLimitPages(1024).WithMemoryCapacityFromMax(true)
+		RuntimeConfig = wazero.NewRuntimeConfig()
 	}
 
 	ctx := context.Background()

tests/parallel/parallel_test.go

@@ -12,9 +12,20 @@ import (
 
 	"github.com/ncruces/go-sqlite3"
 	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/vfs"
 	"github.com/ncruces/go-sqlite3/vfs/memdb"
+	"github.com/tetratelabs/wazero"
 )
 
+func TestMain(m *testing.M) {
+	if vfs.SupportsSharedMemory {
+		sqlite3.RuntimeConfig = wazero.NewRuntimeConfig().
+			WithMemoryCapacityFromMax(true).
+			WithMemoryLimitPages(1024)
+	}
+	os.Exit(m.Run())
+}
+
 func TestParallel(t *testing.T) {
 	var iter int
 	if testing.Short() {
@@ -33,6 +44,10 @@ func TestParallel(t *testing.T) {
 }
 
 func TestWAL(t *testing.T) {
+	if !vfs.SupportsSharedMemory {
+		t.Skip("skipping without shared memory")
+	}
+
 	name := "file:" +
 		filepath.Join(t.TempDir(), "test.db") +
 		"?_pragma=busy_timeout(10000)" +

vfs/lock.go

@@ -1,7 +1,17 @@
+//go:build (linux || darwin || windows || freebsd || openbsd || netbsd || dragonfly || illumos) && !sqlite3_nosys
+
 package vfs
 
 import "github.com/ncruces/go-sqlite3/internal/util"
 
+// SupportsFileLocking is false on platforms that do not support file locking.
+// To open a database file on those platforms,
+// you need to use the [nolock] or [immutable] URI parameters.
+//
+// [nolock]: https://sqlite.org/uri.html#urinolock
+// [immutable]: https://sqlite.org/uri.html#uriimmutable
+const SupportsFileLocking = true
+
 const (
 	_PENDING_BYTE  = 0x40000000
 	_RESERVED_BYTE = (_PENDING_BYTE + 1)

vfs/lock_other.go

@@ -0,0 +1,23 @@
+//go:build !(linux || darwin || windows || freebsd || openbsd || netbsd || dragonfly || illumos) || sqlite3_nosys
+
+package vfs
+
+// SupportsFileLocking is false on platforms that do not support file locking.
+// To open a database file on those platforms,
+// you need to use the [nolock] or [immutable] URI parameters.
+//
+// [nolock]: https://sqlite.org/uri.html#urinolock
+// [immutable]: https://sqlite.org/uri.html#uriimmutable
+const SupportsFileLocking = false
+
+func (f *vfsFile) Lock(LockLevel) error {
+	return _IOERR_LOCK
+}
+
+func (f *vfsFile) Unlock(LockLevel) error {
+	return _IOERR_UNLOCK
+}
+
+func (f *vfsFile) CheckReservedLock() (bool, error) {
+	return false, _IOERR_CHECKRESERVEDLOCK
+}

vfs/os_unix_lock.go

@@ -9,14 +9,6 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-// SupportsFileLocking is false on platforms that do not support file locking.
-// To open a database file in one such platform,
-// you need to use the [nolock] or [immutable] URI parameters.
-//
-// [nolock]: https://sqlite.org/uri.html#urinolock
-// [immutable]: https://sqlite.org/uri.html#uriimmutable
-const SupportsFileLocking = true
-
 func osGetSharedLock(file *os.File) _ErrorCode {
 	// Test the PENDING lock before acquiring a new SHARED lock.
 	if pending, _ := osCheckLock(file, _PENDING_BYTE, 1); pending {

vfs/os_windows.go

@@ -9,14 +9,6 @@ import (
 	"golang.org/x/sys/windows"
 )
 
-// SupportsFileLocking is false on platforms that do not support file locking.
-// To open a database file in one such platform,
-// you need to use the [nolock] or [immutable] URI parameters.
-//
-// [nolock]: https://sqlite.org/uri.html#urinolock
-// [immutable]: https://sqlite.org/uri.html#uriimmutable
-const SupportsFileLocking = true
-
 func osGetSharedLock(file *os.File) _ErrorCode {
 	// Acquire the PENDING lock temporarily before acquiring a new SHARED lock.
 	rc := osReadLock(file, _PENDING_BYTE, 1, 0)

vfs/shm.go

@@ -13,6 +13,16 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// SupportsSharedMemory is true on platforms that support shared memory.
+// To enable shared memory support on those platforms,
+// you need to set the appropriate [wazero.RuntimeConfig];
+// otherwise, [EXCLUSIVE locking mode] is activated automatically
+// to use [WAL without shared-memory].
+//
+// [WAL without shared-memory]: https://sqlite.org/wal.html#noshm
+// [EXCLUSIVE locking mode]: https://sqlite.org/pragma.html#pragma_locking_mode
+const SupportsSharedMemory = true
+
 type vfsShm struct {
 	*os.File
 	regions []shmRegion

vfs/shm_other.go

@@ -8,6 +8,16 @@ import (
 	"github.com/tetratelabs/wazero/api"
 )
 
+// SupportsSharedMemory is true on platforms that support shared memory.
+// To enable shared memory support on those platforms,
+// you need to set the appropriate [wazero.RuntimeConfig];
+// otherwise, [EXCLUSIVE locking mode] is activated automatically
+// to use [WAL without shared-memory].
+//
+// [WAL without shared-memory]: https://sqlite.org/wal.html#noshm
+// [EXCLUSIVE locking mode]: https://sqlite.org/pragma.html#pragma_locking_mode
+const SupportsSharedMemory = false
+
 type vfsShm struct{}
 
 func (f *vfsFile) ShmMap(ctx context.Context, mod api.Module, id, size uint32, extend bool) (uint32, error) {

vfs/tests/mptest/mptest_test.go

@@ -39,8 +39,11 @@ var (
 
 func TestMain(m *testing.M) {
 	ctx := context.Background()
-	rt = wazero.NewRuntimeWithConfig(ctx,
-		wazero.NewRuntimeConfig().WithMemoryLimitPages(1024).WithMemoryCapacityFromMax(true))
+	cfg := wazero.NewRuntimeConfig()
+	if vfs.SupportsSharedMemory {
+		cfg = cfg.WithMemoryLimitPages(1024).WithMemoryCapacityFromMax(true)
+	}
+	rt = wazero.NewRuntimeWithConfig(ctx, cfg)
 	wasi_snapshot_preview1.MustInstantiate(ctx, rt)
 
 	env := vfs.ExportHostFunctions(rt.NewHostModuleBuilder("env"))