diff --git a/c_lib/wasi_ext_lib.h b/c_lib/wasi_ext_lib.h
index 78d77a9..83c1523 100644
--- a/c_lib/wasi_ext_lib.h
+++ b/c_lib/wasi_ext_lib.h
@@ -39,6 +39,10 @@
 
 #define _MAX_FD_NUM 1024
 
+#define WGETGS _IOR(2, 0, 4)
+#define WGETRH _IO(2, 1)
+#define WGETRB _IO(2, 2)
+
 // Extended fs_fdflags
 #define WASI_EXT_FDFLAG_CTRL_BIT ((__wasi_fdflags_t)0x0020)
 #define WASI_EXT_FDFLAG_MASK ((__wasi_fdflags_t)0xffc0)
diff --git a/src/lib.rs b/src/lib.rs
index 5d3f642..dd81a6a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -58,6 +58,10 @@ pub const WASI_EXT_FDFLAG_CTRL_BIT: wasi::Fdflags = 0x0020;
 pub const WASI_EXT_FDFLAG_MASK: wasi::Fdflags = 0xffc0;
 pub const WASI_EXT_FDFLAG_CLOEXEC: wasi::Fdflags = 0x0040;
 
+pub const WGETGS: c_ulong = 2147746304;
+pub const WGETRH: c_ulong = 513;
+pub const WGETRB: c_ulong = 514;
+
 pub use wasi::SIGNAL_KILL;
 
 type ExitCode = i32;