1 files changed, 9 insertions, 1 deletions
diff --git a/test/e2e_harness.zig b/test/e2e_harness.zig
index c188827e..8dac7836 100644
--- a/test/e2e_harness.zig
+++ b/test/e2e_harness.zig
@@ -183,8 +183,16 @@ pub const Harness = struct {
     /// input just sent: without it, an app still asleep in its event loop looks
     /// exactly like an app that has finished. See snapshot.zig's waitStable.
     pub fn pending(self: *Harness) usize {
+        // Darwin files FIONREAD under the socket ioctls rather than the
+        // termios group std.posix.T exposes, and encodes it differently
+        // besides — _IOR('f', 127, int) against linux's flat constant.
+        // Neither is derivable from the other, so both are named.
+        const FIONREAD: c_int = switch (@import("builtin").os.tag) {
+            .linux => posix.T.FIONREAD,
+            else => 0x4004667f,
+        };
         var n: c_int = 0;
-        if (posix.system.ioctl(self.master, posix.T.FIONREAD, @intFromPtr(&n)) != 0) return 0;
+        if (posix.system.ioctl(self.master, FIONREAD, @intFromPtr(&n)) != 0) return 0;
         return if (n > 0) @intCast(n) else 0;
     }