diff --git a/core/sys/win32/general.odin b/core/sys/win32/general.odin
index 51f8c7d5f..d53bf8a4f 100644
--- a/core/sys/win32/general.odin
+++ b/core/sys/win32/general.odin
@@ -99,6 +99,57 @@ Rect :: struct {
 	bottom: i32,
 }
 
+Dev_Mode_A :: struct {
+    device_name:    [32]u8,
+    spec_version:   u16,
+    driver_version: u16,
+    size:           u16,
+    driver_extra:   u16,
+    fields:         u32,
+	using _: struct #raw_union {
+		// Printer only fields.
+		using _: struct {
+			orientation:    i16,
+			paper_size:     i16,
+			paper_length:   i16,
+			paper_width:    i16,
+			scale:          i16,
+			copies:         i16,
+			default_source: i16,
+			print_quality:  i16,
+		},
+		// Display only fields.
+		using _: struct {
+			position:             Point,
+			display_orientation:  u32,
+			display_fixed_output: u32,
+		},
+	},
+    color:        i16,
+    duplex:       i16,
+    y_resolution: i16,
+    tt_option:    i16,
+    collate:      i16,
+    form_name:    [32]u8,
+    log_pixels:   u16,
+    bits_per_pel: u32,
+    pels_width:   u32,
+    pels_height:  u32,
+	using _: struct #raw_union {
+		display_flags: u32,
+		nup:           u32,
+	},
+    display_frequency: u32,
+    icm_method:        u32,
+    icm_intent:        u32,
+    media_type:        u32,
+    dither_type:       u32,
+    reserved_1:        u32,
+    reserved_2:        u32,
+    panning_width:     u32,
+    panning_height:    u32,
+}
+
 Filetime :: struct {
 	lo, hi: u32,
 }
@@ -364,6 +415,9 @@ MAPVK_VK_TO_CHAR   :: 2
 MAPVK_VSC_TO_VK_EX :: 3
 
 //WinUser.h
+ENUM_CURRENT_SETTINGS  :: u32(4294967295) // (DWORD)-1
+ENUM_REGISTRY_SETTINGS :: u32(4294967294) // (DWORD)-2
+
 VK_LBUTTON        :: 0x01
 VK_RBUTTON        :: 0x02
 VK_CANCEL         :: 0x03
@@ -877,7 +931,20 @@ FILE_GENERIC_EXECUTE :: 0x20000000
 FILE_GENERIC_WRITE   :: 0x40000000
 FILE_GENERIC_READ    :: 0x80000000
 
-FILE_APPEND_DATA :: 0x0004
+FILE_READ_DATA            :: 0x0001
+FILE_LIST_DIRECTORY       :: 0x0001
+FILE_WRITE_DATA           :: 0x0002
+FILE_ADD_FILE             :: 0x0002
+FILE_APPEND_DATA          :: 0x0004
+FILE_ADD_SUBDIRECTORY     :: 0x0004
+FILE_CREATE_PIPE_INSTANCE :: 0x0004
+FILE_READ_EA              :: 0x0008
+FILE_WRITE_EA             :: 0x0010
+FILE_EXECUTE              :: 0x0020
+FILE_TRAVERSE             :: 0x0020
+FILE_DELETE_CHILD         :: 0x0040
+FILE_READ_ATTRIBUTES      :: 0x0080
+FILE_WRITE_ATTRIBUTES     :: 0x0100
 
 STD_INPUT_HANDLE  :: -10
 STD_OUTPUT_HANDLE :: -11
diff --git a/core/sys/win32/kernel32.odin b/core/sys/win32/kernel32.odin
index 187bcd06f..709964fb4 100644
--- a/core/sys/win32/kernel32.odin
+++ b/core/sys/win32/kernel32.odin
@@ -106,6 +106,8 @@ foreign kernel32 {
 	                                                                      bytes_returned: ^u32, overlapped: ^Overlapped,
 	                                                                      completion: rawptr) -> Bool ---
 
+	@(link_name="GetOverlappedResult") get_overlapped_result :: proc(file: Handle, overlapped: ^Overlapped, number_of_bytes_transferred: ^u32, wait: Bool) -> Bool ---
+
 	@(link_name="WideCharToMultiByte") wide_char_to_multi_byte :: proc(code_page: u32, flags: u32,
 	                                                                   wchar_str: Wstring, wchar: i32,
 	                                                                   multi_str: cstring, multi: i32,
diff --git a/core/sys/win32/user32.odin b/core/sys/win32/user32.odin
index 57aea88aa..593fdbb8e 100644
--- a/core/sys/win32/user32.odin
+++ b/core/sys/win32/user32.odin
@@ -201,6 +201,8 @@ foreign user32 {
 	@(link_name="MapVirtualKeyExA") map_virtual_key_ex_a :: proc(code, map_type: u32, hkl: HKL) -> u32 ---
 
 	@(link_name="EnumDisplayMonitors") enum_display_monitors :: proc(hdc: Hdc,  rect: ^Rect, enum_proc: Monitor_Enum_Proc, lparam: Lparam) -> bool ---
+
+	@(link_name="EnumDisplaySettingsA") enum_display_settings_a :: proc(device_name: cstring, mode_number: u32, mode: ^Dev_Mode_A) -> Bool ---
 }
 
 @(default_calling_convention = "std")
diff --git a/core/sys/win32/winmm.odin b/core/sys/win32/winmm.odin
index 05d099a1a..0f567fbcc 100644
--- a/core/sys/win32/winmm.odin
+++ b/core/sys/win32/winmm.odin
@@ -6,5 +6,7 @@ foreign import "system:winmm.lib"
 
 @(default_calling_convention = "std")
 foreign winmm {
+    @(link_name="timeBeginPeriod") time_begin_period :: proc(period: u32) -> u32 ---
+
 	@(link_name="timeGetTime") time_get_time :: proc() -> u32 ---
 }