diff --git a/src/cimgui/cimgui.d b/src/cimgui/cimgui.d
index 8c918ad..b0d6efa 100644
--- a/src/cimgui/cimgui.d
+++ b/src/cimgui/cimgui.d
@@ -3,10 +3,15 @@ module cimgui.cimgui;
 // get dcimgui headers to module - @system (unsafe) functions by default
 public import cimgui.dcimgui;
 
-version (Windows)
-    alias dsize_t = ulong;
+version (D_BetterC)
+{
+    // No conflict with object.size_t (DRT)
+}
 else
-    alias dsize_t = size_t;
+{
+    // replace object.size_t to cimgui.dcimgui.size_t
+    version (Windows) alias size_t = ulong;
+}
 
 scope ImGuiContext_t* CreateContext(scope const(ImFontAtlas_t)* shared_font_atlas) @trusted
 {
@@ -801,22 +806,22 @@ void TextLinkOpenURLEx(scope const(char)* label, scope const(char)* url) @truste
     igTextLinkOpenURLEx(label, url);
 }
 
-void Image(dsize_t user_texture_id, const ImVec2_t image_size) @trusted
+void Image(size_t user_texture_id, const ImVec2_t image_size) @trusted
 {
     igImage(user_texture_id, image_size);
 }
 
-void ImageEx(dsize_t user_texture_id, const ImVec2_t image_size, const ImVec2_t uv0, const ImVec2_t uv1, const ImVec4_t tint_col, const ImVec4_t border_col) @trusted
+void ImageEx(size_t user_texture_id, const ImVec2_t image_size, const ImVec2_t uv0, const ImVec2_t uv1, const ImVec4_t tint_col, const ImVec4_t border_col) @trusted
 {
     igImageEx(user_texture_id, image_size, uv0, uv1, tint_col, border_col);
 }
 
-bool ImageButton(scope const(char)* str_id, dsize_t user_texture_id, const ImVec2_t image_size) @trusted
+bool ImageButton(scope const(char)* str_id, size_t user_texture_id, const ImVec2_t image_size) @trusted
 {
     return igImageButton(str_id, user_texture_id, image_size);
 }
 
-bool ImageButtonEx(scope const(char)* str_id, dsize_t user_texture_id, const ImVec2_t image_size, const ImVec2_t uv0, const ImVec2_t uv1, const ImVec4_t bg_col, const ImVec4_t tint_col) @trusted
+bool ImageButtonEx(scope const(char)* str_id, size_t user_texture_id, const ImVec2_t image_size, const ImVec2_t uv0, const ImVec2_t uv1, const ImVec4_t bg_col, const ImVec4_t tint_col) @trusted
 {
     return igImageButtonEx(str_id, user_texture_id, image_size, uv0, uv1, bg_col, tint_col);
 }
@@ -1149,34 +1154,34 @@ bool VSliderScalarEx(scope const(char)* label, ImVec2_t size, int data_type, sco
     return igVSliderScalarEx(label, size, data_type, p_data, p_min, p_max, format, flags);
 }
 
-bool InputText(scope const(char)* label, scope char* buf, dsize_t buf_size, int flags) @trusted
+bool InputText(scope const(char)* label, scope char* buf, size_t buf_size, int flags) @trusted
 {
     return igInputText(label, buf, buf_size, flags);
 }
 
-extern (C) bool InputTextEx(scope const(char)* label, scope char* buf, dsize_t buf_size, int flags, int function(
+extern (C) bool InputTextEx(scope const(char)* label, scope char* buf, size_t buf_size, int flags, int function(
         const ImGuiInputTextCallbackData_t* data) callback, scope void* user_data) @trusted
 {
     return igInputTextEx(label, buf, buf_size, flags, callback, user_data);
 }
 
-bool InputTextMultiline(scope const(char)* label, scope char* buf, dsize_t buf_size) @trusted
+bool InputTextMultiline(scope const(char)* label, scope char* buf, size_t buf_size) @trusted
 {
     return igInputTextMultiline(label, buf, buf_size);
 }
 
-extern (C) bool InputTextMultilineEx(scope const(char)* label, scope char* buf, dsize_t buf_size, ImVec2_t size, int flags, int function(
+extern (C) bool InputTextMultilineEx(scope const(char)* label, scope char* buf, size_t buf_size, ImVec2_t size, int flags, int function(
         const ImGuiInputTextCallbackData_t* data) callback, scope void* user_data) @trusted
 {
     return igInputTextMultilineEx(label, buf, buf_size, size, flags, callback, user_data);
 }
 
-bool InputTextWithHint(scope const(char)* label, scope const(char)* hint, scope char* buf, dsize_t buf_size, int flags) @trusted
+bool InputTextWithHint(scope const(char)* label, scope const(char)* hint, scope char* buf, size_t buf_size, int flags) @trusted
 {
     return igInputTextWithHint(label, hint, buf, buf_size, flags);
 }
 
-extern (C) bool InputTextWithHintEx(scope const(char)* label, scope const(char)* hint, scope char* buf, dsize_t buf_size, int flags, int function(
+extern (C) bool InputTextWithHintEx(scope const(char)* label, scope const(char)* hint, scope char* buf, size_t buf_size, int flags, int function(
         const ImGuiInputTextCallbackData_t* data) callback, scope void* user_data) @trusted
 {
     return igInputTextWithHintEx(label, hint, buf, buf_size, flags, callback, user_data);
@@ -1881,7 +1886,7 @@ bool BeginDragDropSource(int flags) @trusted
     return igBeginDragDropSource(flags);
 }
 
-bool SetDragDropPayload(scope const(char)* type, scope const(void)* data, dsize_t sz, int cond) @trusted
+bool SetDragDropPayload(scope const(char)* type, scope const(void)* data, size_t sz, int cond) @trusted
 {
     return igSetDragDropPayload(type, data, sz, cond);
 }
@@ -2296,7 +2301,7 @@ void LoadIniSettingsFromDisk(scope const(char)* ini_filename) @trusted
     igLoadIniSettingsFromDisk(ini_filename);
 }
 
-void LoadIniSettingsFromMemory(scope const(char)* ini_data, dsize_t ini_size) @trusted
+void LoadIniSettingsFromMemory(scope const(char)* ini_data, size_t ini_size) @trusted
 {
     igLoadIniSettingsFromMemory(ini_data, ini_size);
 }
@@ -2306,7 +2311,7 @@ void SaveIniSettingsToDisk(scope const(char)* ini_filename) @trusted
     igSaveIniSettingsToDisk(ini_filename);
 }
 
-scope const(char)* SaveIniSettingsToMemory(scope dsize_t* out_ini_size) @trusted
+scope const(char)* SaveIniSettingsToMemory(scope size_t* out_ini_size) @trusted
 {
     return igSaveIniSettingsToMemory(out_ini_size);
 }
@@ -2326,7 +2331,7 @@ void DebugStartItemPicker() @trusted
     igDebugStartItemPicker();
 }
 
-bool DebugCheckVersionAndDataLayout(scope const(char)* version_str, dsize_t sz_io, dsize_t sz_style, dsize_t sz_vec2, dsize_t sz_vec4, dsize_t sz_drawvert, dsize_t sz_drawidx) @trusted
+bool DebugCheckVersionAndDataLayout(scope const(char)* version_str, size_t sz_io, size_t sz_style, size_t sz_vec2, size_t sz_vec4, size_t sz_drawvert, size_t sz_drawidx) @trusted
 {
     return igDebugCheckVersionAndDataLayout(version_str, sz_io, sz_style, sz_vec2, sz_vec4, sz_drawvert, sz_drawidx);
 }
@@ -2338,19 +2343,19 @@ void DebugLogV(scope const(char)* fmt, __builtin_va_list args) @trusted
     igDebugLogV(fmt, args);
 }
 
-extern (C) void SetAllocatorFunctions(scope void* function(dsize_t sz, void* user_data) alloc_func, void function(
+extern (C) void SetAllocatorFunctions(scope void* function(size_t sz, void* user_data) alloc_func, void function(
         void* ptr, void* user_data) free_func, scope void* user_data) @trusted
 {
     igSetAllocatorFunctions(alloc_func, free_func, user_data);
 }
 
-extern (C) void GetAllocatorFunctions(scope void* function(dsize_t sz, void* user_data)* p_alloc_func, void function(
+extern (C) void GetAllocatorFunctions(scope void* function(size_t sz, void* user_data)* p_alloc_func, void function(
         void* ptr, void* user_data)* p_free_func, scope void** p_user_data) @trusted
 {
     igGetAllocatorFunctions(p_alloc_func, p_free_func, p_user_data);
 }
 
-scope void* MemAlloc(dsize_t size) @trusted
+scope void* MemAlloc(size_t size) @trusted
 {
     return igMemAlloc(size);
 }
@@ -2769,7 +2774,7 @@ void applyRequests(
     ImGuiSelectionExternalStorage_ApplyRequests(self, ms_io);
 }
 
-dsize_t getTexID(scope const(ImDrawCmd_t)* self) @trusted
+size_t getTexID(scope const(ImDrawCmd_t)* self) @trusted
 {
     return ImDrawCmd_GetTexID(cast(ImDrawCmd_t*) self);
 }