diff --git a/core/sys/darwin/xnu_system_call_wrappers.odin b/core/sys/darwin/xnu_system_call_wrappers.odin
index 99139df6a..43bcb543b 100644
--- a/core/sys/darwin/xnu_system_call_wrappers.odin
+++ b/core/sys/darwin/xnu_system_call_wrappers.odin
@@ -223,6 +223,11 @@ _Proc_Bsdinfo :: struct {
 
 /*--==========================================================================--*/
 
+/* Get window size */
+TIOCGWINSZ :: 0x40087468
+
+/*--==========================================================================--*/
+
 syscall_fsync :: #force_inline proc "contextless" (fildes: c.int) -> bool {
 	return !(cast(bool)intrinsics.syscall(unix_offset_syscall(.fsync), uintptr(fildes)))
 }
diff --git a/core/sys/freebsd/constants.odin b/core/sys/freebsd/constants.odin
new file mode 100644
index 000000000..3188b32d6
--- /dev/null
+++ b/core/sys/freebsd/constants.odin
@@ -0,0 +1,5 @@
+package sys_freebsd
+
+/* Get window size */
+TIOCGWINSZ :: 0x40087468
+
diff --git a/core/sys/linux/constants.odin b/core/sys/linux/constants.odin
index 1010c931a..ceab17f6d 100644
--- a/core/sys/linux/constants.odin
+++ b/core/sys/linux/constants.odin
@@ -391,4 +391,7 @@ MAP_HUGE_256MB      :: transmute(Map_Flags)(u32(28) << MAP_HUGE_SHIFT)
 MAP_HUGE_512MB      :: transmute(Map_Flags)(u32(29) << MAP_HUGE_SHIFT)
 MAP_HUGE_1GB        :: transmute(Map_Flags)(u32(30) << MAP_HUGE_SHIFT)
 MAP_HUGE_2GB        :: transmute(Map_Flags)(u32(31) << MAP_HUGE_SHIFT)
-MAP_HUGE_16GB       :: transmute(Map_Flags)(u32(34) << MAP_HUGE_SHIFT)
\ No newline at end of file
+MAP_HUGE_16GB       :: transmute(Map_Flags)(u32(34) << MAP_HUGE_SHIFT)
+
+/* Get window size */
+TIOCGWINSZ :: 0x5413