diff --git a/src/osd/modules/debugger/win/consolewininfo.cpp b/src/osd/modules/debugger/win/consolewininfo.cpp
index c5e9417487a..0bfaf7debec 100644
--- a/src/osd/modules/debugger/win/consolewininfo.cpp
+++ b/src/osd/modules/debugger/win/consolewininfo.cpp
@@ -286,7 +286,7 @@ bool consolewin_info::handle_command(WPARAM wparam, LPARAM lparam)
 				return true;
 			case DEVOPTION_CLOSE:
 				img->unload();
-				return 1;
+				return true;
 			}
 			if (img->device().type() == CASSETTE)
 			{
diff --git a/src/osd/modules/font/font_dwrite.cpp b/src/osd/modules/font/font_dwrite.cpp
index 71bf43e9794..57b25d87329 100644
--- a/src/osd/modules/font/font_dwrite.cpp
+++ b/src/osd/modules/font/font_dwrite.cpp
@@ -348,7 +348,7 @@ public:
 	{
 	}
 
-	virtual ~osd_font_dwrite() { close(); }
+	virtual ~osd_font_dwrite() { osd_font_dwrite::close(); }
 	
 	virtual bool open(std::string const &font_path, std::string const &_name, int &height) override
 	{
diff --git a/src/osd/modules/input/input_dinput.h b/src/osd/modules/input/input_dinput.h
index 594b46f6732..87e25a3a1ab 100644
--- a/src/osd/modules/input/input_dinput.h
+++ b/src/osd/modules/input/input_dinput.h
@@ -134,7 +134,7 @@ public:
 
 	HRESULT enum_attached_devices(int devclass, device_enum_interface *enumerate_interface, void *state) const;
 
-	const std::string guid_to_string(const GUID& guid)
+	std::string guid_to_string(const GUID& guid) const
 	{
 		char guid_string[37];
 		sprintf_s(
diff --git a/src/osd/modules/lib/osdobj_common.cpp b/src/osd/modules/lib/osdobj_common.cpp
index 3f4763626fa..6e36fe7a920 100644
--- a/src/osd/modules/lib/osdobj_common.cpp
+++ b/src/osd/modules/lib/osdobj_common.cpp
@@ -342,7 +342,7 @@ void osd_common_t::register_options()
 	update_option(OSDOPTION_VIDEO, m_video_names);
 }
 
-void osd_common_t::update_option(const char * key, std::vector<const char *> &values)
+void osd_common_t::update_option(const char * key, std::vector<const char *> &values) const
 {
 	std::string current_value(m_options.description(key));
 	std::string new_option_value("");
@@ -625,8 +625,7 @@ bool osd_common_t::execute_command(const char *command)
 
 static void output_notifier_callback(const char *outname, int32_t value, void *param)
 {
-	osd_common_t *osd = (osd_common_t*)param;
-	osd->notify(outname, value);
+	static_cast<osd_common_t*>(param)->notify(outname, value);
 }
 
 void osd_common_t::init_subsystems()
diff --git a/src/osd/modules/lib/osdobj_common.h b/src/osd/modules/lib/osdobj_common.h
index 13d8d81c99d..5ae94d7a699 100644
--- a/src/osd/modules/lib/osdobj_common.h
+++ b/src/osd/modules/lib/osdobj_common.h
@@ -257,7 +257,7 @@ private:
 	osd_module_manager m_mod_man;
 	font_module *m_font_module;
 
-	void update_option(const char * key, std::vector<const char *> &values);
+	void update_option(const char * key, std::vector<const char *> &values) const;
 	// FIXME: should be elsewhere
 	osd_module *select_module_options(const core_options &opts, const std::string &opt_name)
 	{
diff --git a/src/osd/modules/monitor/monitor_common.h b/src/osd/modules/monitor/monitor_common.h
index 9529f8f900b..4316722c9bb 100644
--- a/src/osd/modules/monitor/monitor_common.h
+++ b/src/osd/modules/monitor/monitor_common.h
@@ -4,6 +4,8 @@
 * monitor_common.h
 *
 */
+#ifndef __MONITOR_COMMON_H__
+#define __MONITOR_COMMON_H__
 
 #include "modules/lib/osdobj_common.h"
 #include <map>
@@ -41,3 +43,5 @@ private:
 	std::shared_ptr<osd_monitor_info> pick_monitor_internal(osd_options& options, int index);
 	static float get_aspect(const char *defdata, const char *data, int report_error);
 };
+
+#endif
diff --git a/src/osd/modules/netdev/pcap.cpp b/src/osd/modules/netdev/pcap.cpp
index c8131f88c3b..ad49a399304 100644
--- a/src/osd/modules/netdev/pcap.cpp
+++ b/src/osd/modules/netdev/pcap.cpp
@@ -41,9 +41,12 @@ class pcap_module : public osd_module, public netdev_module
 {
 public:
 	pcap_module()
-	: osd_module(OSD_NETDEV_PROVIDER, "pcap"), netdev_module()
+		: osd_module(OSD_NETDEV_PROVIDER, "pcap"), netdev_module(),
+		  pcap_findalldevs_dl(nullptr), pcap_open_live_dl(nullptr), pcap_next_ex_dl(nullptr), pcap_compile_dl(nullptr),
+		  pcap_close_dl(nullptr), pcap_setfilter_dl(nullptr), pcap_sendpacket_dl(nullptr), pcap_set_datalink_dl(nullptr), pcap_dispatch_dl(nullptr)
 	{
 	}
+
 	virtual ~pcap_module() { }
 
 	virtual int init(const osd_options &options) override;
diff --git a/src/osd/modules/osdwindow.h b/src/osd/modules/osdwindow.h
index da4385cc084..9a38918671c 100644
--- a/src/osd/modules/osdwindow.h
+++ b/src/osd/modules/osdwindow.h
@@ -71,7 +71,7 @@ class osd_window : public std::enable_shared_from_this<osd_window>
 public:
 	osd_window(const osd_window_config &config)
 	:
-#ifdef OSD_WINDOW
+#ifdef OSD_WINDOWS
 		m_dc(nullptr), m_resize_state(0),
 #endif
 		m_primlist(nullptr),
@@ -83,6 +83,8 @@ public:
 		m_main(nullptr)
 		{}
 
+	virtual ~osd_window() { }
+
 	virtual render_target *target() = 0;
 	virtual int fullscreen() const = 0;
 	virtual running_machine &machine() const = 0;
diff --git a/src/osd/modules/output/win32_output.cpp b/src/osd/modules/output/win32_output.cpp
index 26eb37643a9..6ae431de099 100644
--- a/src/osd/modules/output/win32_output.cpp
+++ b/src/osd/modules/output/win32_output.cpp
@@ -67,7 +67,7 @@ class output_win32 : public osd_module, public output_module
 {
 public:
 	output_win32()
-		: osd_module(OSD_OUTPUT_PROVIDER, "windows"), output_module()
+		: osd_module(OSD_OUTPUT_PROVIDER, "windows"), output_module(), m_output_hwnd(nullptr), m_clientlist(nullptr)
 	{
 	}
 	virtual ~output_win32() { }
diff --git a/src/osd/modules/render/d3d/d3dhlsl.cpp b/src/osd/modules/render/d3d/d3dhlsl.cpp
index 32836477810..dff6082745e 100644
--- a/src/osd/modules/render/d3d/d3dhlsl.cpp
+++ b/src/osd/modules/render/d3d/d3dhlsl.cpp
@@ -165,13 +165,13 @@ private:
 shaders::shaders() :
 	d3dintf(nullptr), machine(nullptr), d3d(nullptr), post_fx_enable(false), oversampling_enable(false),
 	num_screens(0), curr_screen(0), shadow_texture(nullptr), options(nullptr), black_surface(nullptr),
-	black_texture(nullptr), recording_movie(false),render_snap(false), snap_copy_target(nullptr),
+	black_texture(nullptr), recording_movie(false), render_snap(false), snap_copy_target(nullptr),
 	snap_copy_texture(nullptr), snap_target(nullptr), snap_texture(nullptr), snap_width(0), snap_height(0),
 	initialized(false), backbuffer(nullptr), curr_effect(nullptr), default_effect(nullptr),
 	prescale_effect(nullptr), post_effect(nullptr), distortion_effect(nullptr), focus_effect(nullptr),
 	phosphor_effect(nullptr), deconverge_effect(nullptr), color_effect(nullptr), ntsc_effect(nullptr),
 	bloom_effect(nullptr), downsample_effect(nullptr), vector_effect(nullptr), curr_texture(nullptr),
-	curr_render_target(nullptr), curr_poly(nullptr)
+	curr_render_target(nullptr), curr_poly(nullptr), d3dx_create_effect_from_file_ptr(nullptr)
 {
 }
 
diff --git a/src/osd/modules/render/drawnone.h b/src/osd/modules/render/drawnone.h
index 1fc4a50b689..c884f969204 100644
--- a/src/osd/modules/render/drawnone.h
+++ b/src/osd/modules/render/drawnone.h
@@ -6,14 +6,11 @@
 //
 //============================================================
 
-// MAMEOS headers
-#include "window.h"
-
-#pragma once
-
 #ifndef __DRAWNONE__
 #define __DRAWNONE__
 
+#include "window.h"
+
 class renderer_none : public osd_renderer
 {
 public:
diff --git a/src/osd/osdnet.h b/src/osd/osdnet.h
index 8dacfe29fdb..9725d76536c 100644
--- a/src/osd/osdnet.h
+++ b/src/osd/osdnet.h
@@ -1,10 +1,10 @@
 // license:BSD-3-Clause
 // copyright-holders:Carl
-#include "emu.h"
-
 #ifndef __OSDNET_H__
 #define __OSDNET_H__
 
+#include "emu.h"
+
 class osd_netdev;
 
 #define CREATE_NETDEV(name) class osd_netdev *name(const char *ifname, class device_network_interface *ifdev, int rate)
diff --git a/src/osd/uwp/video.cpp b/src/osd/uwp/video.cpp
index 1462ff5b81b..51c7cc60c34 100644
--- a/src/osd/uwp/video.cpp
+++ b/src/osd/uwp/video.cpp
@@ -104,7 +104,7 @@ void windows_osd_interface::update(bool skip_redraw)
 	}
 
 	// poll the joystick values here
-	winwindow_process_events(machine(), TRUE, FALSE);
+	winwindow_process_events(machine(), true, false);
 	poll_input(machine());
 	check_osd_inputs();
 	// if we're running, disable some parts of the debugger
diff --git a/src/osd/uwp/window.cpp b/src/osd/uwp/window.cpp
index 81d20f358c9..870584772b2 100644
--- a/src/osd/uwp/window.cpp
+++ b/src/osd/uwp/window.cpp
@@ -314,7 +314,7 @@ void winwindow_process_events_periodic(running_machine &machine)
 	// update once every 1/8th of a second
 	if (currticks - last_event_check < std::chrono::milliseconds(1000 / 8))
 		return;
-	winwindow_process_events(machine, TRUE, false);
+	winwindow_process_events(machine, true, false);
 }
 
 //============================================================
@@ -359,7 +359,7 @@ inline static BOOL handle_keypress(windows_osd_interface *osd, int vkey, int dow
 //  (main thread)
 //============================================================
 
-void winwindow_process_events(running_machine &machine, int ingame, bool nodispatch)
+void winwindow_process_events(running_machine &machine, bool ingame, bool nodispatch)
 {
 //	MSG message;
 
diff --git a/src/osd/uwp/window.h b/src/osd/uwp/window.h
index 449db252e7b..b95676b40fb 100644
--- a/src/osd/uwp/window.h
+++ b/src/osd/uwp/window.h
@@ -157,7 +157,7 @@ struct osd_draw_callbacks
 //============================================================
 
 BOOL winwindow_has_focus(void);
-void winwindow_process_events(running_machine &machine, int ingame, bool nodispatch);
+void winwindow_process_events(running_machine &machine, bool ingame, bool nodispatch);
 void winwindow_process_events_periodic(running_machine &machine);
 
 //============================================================
diff --git a/src/osd/windows/video.cpp b/src/osd/windows/video.cpp
index f752d28e29c..9d86fb63301 100644
--- a/src/osd/windows/video.cpp
+++ b/src/osd/windows/video.cpp
@@ -97,7 +97,7 @@ void windows_osd_interface::update(bool skip_redraw)
 	}
 
 	// poll the joystick values here
-	winwindow_process_events(machine(), TRUE, FALSE);
+	winwindow_process_events(machine(), true, false);
 	poll_input(machine());
 	check_osd_inputs();
 	// if we're running, disable some parts of the debugger
diff --git a/src/osd/windows/window.cpp b/src/osd/windows/window.cpp
index c9c55f138da..b71ccae5c2b 100644
--- a/src/osd/windows/window.cpp
+++ b/src/osd/windows/window.cpp
@@ -411,7 +411,7 @@ void winwindow_process_events_periodic(running_machine &machine)
 	// update once every 1/8th of a second
 	if (currticks - last_event_check < std::chrono::milliseconds(1000 / 8))
 		return;
-	winwindow_process_events(machine, TRUE, false);
+	winwindow_process_events(machine, true, false);
 }
 
 
@@ -460,7 +460,7 @@ inline static BOOL handle_keypress(windows_osd_interface *osd, int vkey, int dow
 //  (main thread)
 //============================================================
 
-void winwindow_process_events(running_machine &machine, int ingame, bool nodispatch)
+void winwindow_process_events(running_machine &machine, bool ingame, bool nodispatch)
 {
 	MSG message;
 
diff --git a/src/osd/windows/window.h b/src/osd/windows/window.h
index e58dfcae44d..fa78efc2b2a 100644
--- a/src/osd/windows/window.h
+++ b/src/osd/windows/window.h
@@ -169,7 +169,7 @@ void winwindow_take_video(void);
 void winwindow_toggle_fsfx(void);
 
 void winwindow_process_events_periodic(running_machine &machine);
-void winwindow_process_events(running_machine &machine, int ingame, bool nodispatch);
+void winwindow_process_events(running_machine &machine, bool ingame, bool nodispatch);
 
 void winwindow_ui_pause(running_machine &machine, int pause);
 int winwindow_ui_is_paused(running_machine &machine);
diff --git a/src/osd/windows/winmain.cpp b/src/osd/windows/winmain.cpp
index 3116aa16730..22283f89ebf 100644
--- a/src/osd/windows/winmain.cpp
+++ b/src/osd/windows/winmain.cpp
@@ -589,7 +589,7 @@ void windows_osd_interface::osd_exit()
 #endif
 
 	// one last pass at events
-	winwindow_process_events(machine(), 0, 0);
+	winwindow_process_events(machine(), false, false);
 }