diff --git a/src/c.zig b/src/c.zig
index 04d6023..46975dc 100644
--- a/src/c.zig
+++ b/src/c.zig
@@ -3,13 +3,22 @@ pub const c = @cImport({
     @cInclude("objc/message.h");
 });
 
-/// This is a funky helper to help with the fact that some macOS
-/// SDKs have an i8 return value for bools and some have stdbool.
-pub fn boolResult(comptime Fn: type, result: anytype) bool {
-    const fn_info = @typeInfo(Fn).@"fn";
-    return switch (fn_info.return_type.?) {
+/// On some targets, Objective-C uses `i8` instead of `bool`.
+/// This helper casts a target value type to `bool`.
+pub fn boolResult(result: c.BOOL) bool {
+    return switch (c.BOOL) {
         bool => result,
         i8 => result == 1,
-        else => @compileError("unhandled class_addIvar return type"),
+        else => @compileError("unexpected boolean type"),
+    };
+}
+
+/// On some targets, Objective-C uses `i8` instead of `bool`.
+/// This helper casts a `bool` value to the target value type.
+pub fn boolParam(param: bool) c.BOOL {
+    return switch (c.BOOL) {
+        bool => param,
+        i8 => @intFromBool(param),
+        else => @compileError("unexpected boolean type"),
     };
 }
diff --git a/src/class.zig b/src/class.zig
index 4691698..bf92b7c 100644
--- a/src/class.zig
+++ b/src/class.zig
@@ -38,7 +38,7 @@ pub const Class = struct {
     }
 
     pub fn isMetaClass(self: Class) bool {
-        return c.class_isMetaClass(self.value) == 1;
+        return boolResult(c.class_isMetaClass(self.value));
     }
 
     pub fn getInstanceSize(self: Class) usize {
@@ -46,11 +46,11 @@ pub const Class = struct {
     }
 
     pub fn respondsToSelector(self: Class, sel: objc.Sel) bool {
-        return c.class_respondsToSelector(self.value, sel.value) == 1;
+        return boolResult(c.class_respondsToSelector(self.value, sel.value));
     }
 
     pub fn conformsToProtocol(self: Class, protocol: objc.Protocol) bool {
-        return c.class_conformsToProtocol(self.value, &protocol.value) == 1;
+        return boolResult(c.class_conformsToProtocol(self.value, &protocol.value));
     }
 
     // currently only allows for overriding methods previously defined, e.g. by a superclass.
@@ -78,7 +78,7 @@ pub const Class = struct {
         assert(fn_info.params[0].type == c.id);
         assert(fn_info.params[1].type == c.SEL);
         const encoding = comptime objc.comptimeEncode(Fn);
-        return boolResult(@TypeOf(c.class_addMethod), c.class_addMethod(
+        return boolResult(c.class_addMethod(
             self.value,
             objc.sel(name).value,
             @ptrCast(&imp),
@@ -91,7 +91,7 @@ pub const Class = struct {
     pub fn addIvar(self: Class, name: [:0]const u8) bool {
         // The return type is i8 when we're cross compiling, unsure why.
         const result = c.class_addIvar(self.value, name, @sizeOf(c.id), @alignOf(c.id), "@");
-        return boolResult(@TypeOf(c.class_addIvar), result);
+        return boolResult(result);
     }
 };
 
diff --git a/src/object.zig b/src/object.zig
index d80b611..73fd485 100644
--- a/src/object.zig
+++ b/src/object.zig
@@ -1,5 +1,7 @@
 const std = @import("std");
-const c = @import("c.zig").c;
+const cpkg = @import("c.zig");
+const c = cpkg.c;
+const boolResult = cpkg.boolResult;
 const objc = @import("main.zig");
 const MsgSend = @import("msg_send.zig").MsgSend;
 const Iterator = @import("iterator.zig").Iterator;
@@ -102,7 +104,7 @@ pub const Object = struct {
     }
 
     pub fn isClass(self: Object) bool {
-        return c.object_isClass(self.value) == 1;
+        return boolResult(c.object_isClass(self.value));
     }
 
     pub fn getInstanceVariable(self: Object, name: [:0]const u8) Object {
diff --git a/src/protocol.zig b/src/protocol.zig
index e72e170..24b64b0 100644
--- a/src/protocol.zig
+++ b/src/protocol.zig
@@ -1,16 +1,19 @@
 const std = @import("std");
-const c = @import("c.zig").c;
+const cpkg = @import("c.zig");
+const c = cpkg.c;
+const boolParam = cpkg.boolParam;
+const boolResult = cpkg.boolResult;
 const objc = @import("main.zig");
 
 pub const Protocol = extern struct {
     value: *c.Protocol,
 
     pub fn conformsToProtocol(self: Protocol, other: Protocol) bool {
-        return c.protocol_conformsToProtocol(self.value, other.value) == 1;
+        return boolResult(c.protocol_conformsToProtocol(self.value, other.value));
     }
 
     pub fn isEqual(self: Protocol, other: Protocol) bool {
-        return c.protocol_isEqual(self.value, other.value) == 1;
+        return boolResult(c.protocol_isEqual(self.value, other.value));
     }
 
     pub fn getName(self: Protocol) [:0]const u8 {
@@ -23,13 +26,11 @@ pub const Protocol = extern struct {
         is_required: bool,
         is_instance: bool,
     ) ?objc.Property {
-        const isRequired: u8 = if (is_required) 1 else 0;
-        const isInstance: u8 = if (is_instance) 1 else 0;
         return .{ .value = c.protocol_getProperty(
             self.value,
             name,
-            isRequired,
-            isInstance,
+            boolParam(is_required),
+            boolParam(is_instance),
         ) orelse return null };
     }
 
@@ -42,3 +43,18 @@ pub const Protocol = extern struct {
 pub fn getProtocol(name: [:0]const u8) ?Protocol {
     return .{ .value = c.objc_getProtocol(name) orelse return null };
 }
+
+test Protocol {
+    const testing = std.testing;
+    const fs_proto = getProtocol("NSFileManagerDelegate") orelse return error.ProtocolNotFound;
+    try testing.expectEqualStrings("NSFileManagerDelegate", fs_proto.getName());
+
+    const obj_proto = getProtocol("NSObject") orelse return error.ProtocolNotFound;
+    try testing.expect(fs_proto.conformsToProtocol(obj_proto));
+
+    const url_proto = getProtocol("NSURLSessionDelegate") orelse return error.ProtocolNotFound;
+    try testing.expect(!fs_proto.conformsToProtocol(url_proto));
+
+    const hash_prop = obj_proto.getProperty("hash", true, true) orelse return error.ProtocolPropertyNotFound;
+    try testing.expectEqualStrings("hash", hash_prop.getName());
+}