diff --git a/src/gphoto2/camera_widgets/date.cr b/src/gphoto2/camera_widgets/date.cr
index 41a8bcd..9c613ad 100644
--- a/src/gphoto2/camera_widgets/date.cr
+++ b/src/gphoto2/camera_widgets/date.cr
@@ -12,7 +12,7 @@ module GPhoto2
       protected def set_value(value)
         case value
         when Time
-          ptr = Pointer(LibC::Int).malloc 1, value.to_unix.to_i32
+          ptr = Pointer(LibC::Int).malloc 1, LibC::Int.new(value.to_unix.to_i32)
           set_value_ptr ptr
         when Int
           set_value Time.unix(value)
diff --git a/src/gphoto2/camera_widgets/range.cr b/src/gphoto2/camera_widgets/range.cr
index f1b6f9f..1b72bdb 100644
--- a/src/gphoto2/camera_widgets/range.cr
+++ b/src/gphoto2/camera_widgets/range.cr
@@ -34,7 +34,7 @@ module GPhoto2
       protected def set_value(value)
         case value
         when Float
-          ptr = Pointer(LibC::Float).malloc 1, value.to_f32
+          ptr = Pointer(LibC::Float).malloc 1, LibC::Float.new(value.to_f32)
           set_value_ptr ptr
         when Int, String
           set_value value.to_f32
diff --git a/src/gphoto2/camera_widgets/toggle.cr b/src/gphoto2/camera_widgets/toggle.cr
index c667bdf..a4102c8 100644
--- a/src/gphoto2/camera_widgets/toggle.cr
+++ b/src/gphoto2/camera_widgets/toggle.cr
@@ -12,7 +12,7 @@ module GPhoto2
       protected def set_value(value)
         case value
         when Int
-          ptr = Pointer(LibC::Int).malloc 1, value.to_i32
+          ptr = Pointer(LibC::Int).malloc 1, LibC::Int.new(value.to_i32)
           set_value_ptr ptr
         when Bool
           set_value value ? 1 : 0