diff --git a/ext/-test-/memory_view/memory_view.c b/ext/-test-/memory_view/memory_view.c
index c85ba6fbfa..00572b9109 100644
--- a/ext/-test-/memory_view/memory_view.c
+++ b/ext/-test-/memory_view/memory_view.c
@@ -24,15 +24,15 @@ static VALUE sym_endianness;
 static VALUE sym_little_endian;
 static VALUE sym_big_endian;
 
-static int
+static bool
 exportable_string_get_memory_view(VALUE obj, rb_memory_view_t *view, int flags)
 {
     VALUE str = rb_ivar_get(obj, id_str);
     rb_memory_view_init_as_byte_array(view, obj, RSTRING_PTR(str), RSTRING_LEN(str), true);
-    return 1;
+    return true;
 }
 
-static int
+static bool
 exportable_string_memory_view_available_p(VALUE obj)
 {
     VALUE str = rb_ivar_get(obj, id_str);
@@ -260,7 +260,7 @@ expstr_initialize(VALUE obj, VALUE s)
     return Qnil;
 }
 
-static int
+static bool
 mdview_get_memory_view(VALUE obj, rb_memory_view_t *view, int flags)
 {
     VALUE buf_v = rb_ivar_get(obj, id_str);
@@ -272,7 +272,7 @@ mdview_get_memory_view(VALUE obj, rb_memory_view_t *view, int flags)
     const char *err;
     const ssize_t item_size = rb_memory_view_item_size_from_format(format, &err);
     if (item_size < 0) {
-        return 0;
+        return false;
     }
 
     ssize_t ndim = RARRAY_LEN(shape_v);
@@ -308,10 +308,10 @@ mdview_get_memory_view(VALUE obj, rb_memory_view_t *view, int flags)
     view->shape = shape;
     view->strides = strides;
 
-    return 1;
+    return true;
 }
 
-static int
+static bool
 mdview_memory_view_available_p(VALUE obj)
 {
     return true;
diff --git a/ext/fiddle/pointer.c b/ext/fiddle/pointer.c
index ca1d59ff5f..c5fb442aec 100644
--- a/ext/fiddle/pointer.c
+++ b/ext/fiddle/pointer.c
@@ -102,19 +102,19 @@ fiddle_ptr_check_memory_view(VALUE obj)
     return data;
 }
 
-static int
+static bool
 fiddle_ptr_memory_view_available_p(VALUE obj)
 {
     return fiddle_ptr_check_memory_view(obj) != NULL;
 }
 
-static int
+static bool
 fiddle_ptr_get_memory_view(VALUE obj, rb_memory_view_t *view, int flags)
 {
     struct ptr_data *data = fiddle_ptr_check_memory_view(obj);
     rb_memory_view_init_as_byte_array(view, obj, data->ptr, data->size, true);
 
-    return 1;
+    return true;
 }
 
 static const rb_memory_view_entry_t fiddle_ptr_memory_view_entry = {
diff --git a/include/ruby/memory_view.h b/include/ruby/memory_view.h
index 29d8f7059d..b90a32d96e 100644
--- a/include/ruby/memory_view.h
+++ b/include/ruby/memory_view.h
@@ -48,7 +48,7 @@ typedef struct {
     /* The number of bytes in data. */
     ssize_t len;
 
-    /* 1 for readonly memory, 0 for writable memory. */
+    /* true for readonly memory, false for writable memory. */
     bool readonly;
 
     /* A string to describe the format of an element, or NULL for unsigned byte.
@@ -105,9 +105,9 @@ typedef struct {
     void *const private;
 } rb_memory_view_t;
 
-typedef int (* rb_memory_view_get_func_t)(VALUE obj, rb_memory_view_t *view, int flags);
-typedef int (* rb_memory_view_release_func_t)(VALUE obj, rb_memory_view_t *view);
-typedef int (* rb_memory_view_available_p_func_t)(VALUE obj);
+typedef bool (* rb_memory_view_get_func_t)(VALUE obj, rb_memory_view_t *view, int flags);
+typedef bool (* rb_memory_view_release_func_t)(VALUE obj, rb_memory_view_t *view);
+typedef bool (* rb_memory_view_available_p_func_t)(VALUE obj);
 
 typedef struct {
     rb_memory_view_get_func_t get_func;
@@ -127,7 +127,7 @@ bool rb_memory_view_is_column_major_contiguous(const rb_memory_view_t *view);
 RBIMPL_ATTR_NOALIAS()
 void rb_memory_view_fill_contiguous_strides(const ssize_t ndim, const ssize_t item_size, const ssize_t *const shape, const bool row_major_p, ssize_t *const strides);
 RBIMPL_ATTR_NOALIAS()
-int rb_memory_view_init_as_byte_array(rb_memory_view_t *view, VALUE obj, void *data, const ssize_t len, const bool readonly);
+bool rb_memory_view_init_as_byte_array(rb_memory_view_t *view, VALUE obj, void *data, const ssize_t len, const bool readonly);
 ssize_t rb_memory_view_parse_item_format(const char *format,
                                          rb_memory_view_item_component_t **members,
                                          size_t *n_members, const char **err);
@@ -137,9 +137,9 @@ VALUE rb_memory_view_extract_item_members(const void *ptr, const rb_memory_view_
 void rb_memory_view_prepare_item_desc(rb_memory_view_t *view);
 VALUE rb_memory_view_get_item(rb_memory_view_t *view, const ssize_t *indices);
 
-int rb_memory_view_available_p(VALUE obj);
-int rb_memory_view_get(VALUE obj, rb_memory_view_t* memory_view, int flags);
-int rb_memory_view_release(rb_memory_view_t* memory_view);
+bool rb_memory_view_available_p(VALUE obj);
+bool rb_memory_view_get(VALUE obj, rb_memory_view_t* memory_view, int flags);
+bool rb_memory_view_release(rb_memory_view_t* memory_view);
 
 /* for testing */
 RUBY_EXTERN VALUE rb_memory_view_exported_object_registry;
diff --git a/memory_view.c b/memory_view.c
index 7a2a518647..08ff967a1b 100644
--- a/memory_view.c
+++ b/memory_view.c
@@ -194,7 +194,7 @@ rb_memory_view_fill_contiguous_strides(const ssize_t ndim, const ssize_t item_si
 }
 
 /* Initialize view to expose a simple byte array */
-int
+bool
 rb_memory_view_init_as_byte_array(rb_memory_view_t *view, VALUE obj, void *data, const ssize_t len, const bool readonly)
 {
     view->obj = obj;
@@ -211,7 +211,7 @@ rb_memory_view_init_as_byte_array(rb_memory_view_t *view, VALUE obj, void *data,
     view->sub_offsets = NULL;
     *((void **)&view->private) = NULL;
 
-    return 1;
+    return true;
 }
 
 #ifdef HAVE_TRUE_LONG_LONG
@@ -794,7 +794,7 @@ lookup_memory_view_entry(VALUE klass)
 }
 
 /* Examine whether the given object supports memory view. */
-int
+bool
 rb_memory_view_available_p(VALUE obj)
 {
     VALUE klass = CLASS_OF(obj);
@@ -802,38 +802,38 @@ rb_memory_view_available_p(VALUE obj)
     if (entry)
         return (* entry->available_p_func)(obj);
     else
-        return 0;
+        return false;
 }
 
 /* Obtain a memory view from obj, and substitute the information to view. */
-int
+bool
 rb_memory_view_get(VALUE obj, rb_memory_view_t* view, int flags)
 {
     VALUE klass = CLASS_OF(obj);
     const rb_memory_view_entry_t *entry = lookup_memory_view_entry(klass);
     if (entry) {
         if (!(*entry->available_p_func)(obj)) {
-            return 0;
+            return false;
         }
 
-        int rv = (*entry->get_func)(obj, view, flags);
+        bool rv = (*entry->get_func)(obj, view, flags);
         if (rv) {
             register_exported_object(view->obj);
         }
         return rv;
     }
     else
-        return 0;
+        return false;
 }
 
 /* Release the memory view obtained from obj. */
-int
+bool
 rb_memory_view_release(rb_memory_view_t* view)
 {
     VALUE klass = CLASS_OF(view->obj);
     const rb_memory_view_entry_t *entry = lookup_memory_view_entry(klass);
     if (entry) {
-        int rv = 1;
+        bool rv = true;
         if (entry->release_func) {
             rv = (*entry->release_func)(view->obj, view);
         }
@@ -847,7 +847,7 @@ rb_memory_view_release(rb_memory_view_t* view)
         return rv;
     }
     else
-        return 0;
+        return false;
 }
 
 void