diff --git a/build.zig b/build.zig
index da0fce5..6109544 100644
--- a/build.zig
+++ b/build.zig
@@ -155,6 +155,41 @@ const MakeDirStep = struct {
     }
 };
 
+const WriteStaticFileStep = struct {
+    step: std.Build.Step,
+    path: []const u8,
+    contents: []const u8,
+
+    pub fn create(b: *std.Build, path: []const u8, contents: []const u8) *std.Build.Step {
+        const self = b.allocator.create(WriteStaticFileStep) catch @panic("OOM");
+        self.* = .{
+            .step = std.Build.Step.init(.{
+                .id = .custom,
+                .name = b.fmt("write {s}", .{path}),
+                .owner = b,
+                .makeFn = make,
+            }),
+            .path = b.dupe(path),
+            .contents = b.dupe(contents),
+        };
+        return &self.step;
+    }
+
+    fn make(step: *std.Build.Step, options: std.Build.Step.MakeOptions) !void {
+        _ = options;
+        const self: *WriteStaticFileStep = @fieldParentPtr("step", step);
+
+        if (std.fs.path.dirname(self.path)) |dir| {
+            try std.fs.cwd().makePath(dir);
+        }
+
+        try std.fs.cwd().writeFile(.{
+            .sub_path = self.path,
+            .data = self.contents,
+        });
+    }
+};
+
 pub fn generateApi(b: *std.Build, parser_exe: *std.Build.Step.Compile, fetch_sdl_step: *std.Build.Step) void {
     const source_dir = b.option([]const u8, "sourceDir", "Parse SDL headers from an existing local directory instead of fetching git");
     const output_dir = b.option([]const u8, "outputDir", "Directory where generated api/ and json/ folders should be written");
@@ -190,8 +225,30 @@ pub fn generateApi(b: *std.Build, parser_exe: *std.Build.Step.Compile, fetch_sdl
         path_prep_step = basedir_step;
     }
 
-    // All public SDL3 API headers (53 total)
-    // Skipped: assert, thread, hidapi, mutex, tray (not core APIs or problematic)
+    const output_root = if (effective_output_dir) |dir| b.fmt("{s}/api", .{dir}) else "api";
+    const json_root = if (effective_output_dir) |dir| b.fmt("{s}/json", .{dir}) else "json";
+    const effective_c_import_path = c_import_path orelse "c.zig";
+    const c_bridge_target = if (c_import_path) |path| path else "../c.zig";
+    const c_bridge_step = WriteStaticFileStep.create(
+        b,
+        b.fmt("{s}/c.zig", .{output_root}),
+        b.fmt("pub const c = @import(\"{s}\").c;\n", .{c_bridge_target}),
+    );
+    c_bridge_step.dependOn(path_prep_step);
+    path_prep_step = c_bridge_step;
+
+    const stdinc_bridge_step = WriteStaticFileStep.create(
+        b,
+        b.fmt("{s}/stdinc.zig", .{output_root}),
+        \\pub const c = @import("c.zig").c;
+        \\pub const Time = i64;
+        \\pub const FunctionPointer = c.SDL_FunctionPointer;
+        \\
+    );
+    stdinc_bridge_step.dependOn(path_prep_step);
+    path_prep_step = stdinc_bridge_step;
+
+    // All public SDL3 API headers
     const headers_to_generate = [_]struct { header: []const u8, output: []const u8 }{
         // .{ .header = "SDL_asyncio.h", .output = "asyncio" },
         // .{ .header = "SDL_atomic.h", .output = "atomic" },
@@ -212,7 +269,7 @@ pub fn generateApi(b: *std.Build, parser_exe: *std.Build.Step.Compile, fetch_sdl
         // .{ .header = "SDL_hidapi.h", .output = "hidapi" }, // Skipped: not core API
         .{ .header = "SDL_hints.h", .output = "hints" },
         .{ .header = "SDL_init.h", .output = "init" },
-        // .{ .header = "SDL_iostream.h", .output = "iostream" }, // Skipped: complex I/O API
+        .{ .header = "SDL_iostream.h", .output = "iostream" },
         .{ .header = "SDL_joystick.h", .output = "joystick" },
         .{ .header = "SDL_keyboard.h", .output = "keyboard" },
         .{ .header = "SDL_keycode.h", .output = "keycode" },
@@ -252,9 +309,6 @@ pub fn generateApi(b: *std.Build, parser_exe: *std.Build.Step.Compile, fetch_sdl
         b.fmt("{s}/{s}", .{ dir, header_root_suffix.? })
     else
         "sdl3/include/SDL3";
-    const output_root = if (effective_output_dir) |dir| b.fmt("{s}/api", .{dir}) else "api";
-    const json_root = if (effective_output_dir) |dir| b.fmt("{s}/json", .{dir}) else "json";
-
     const timestamp_arg = b.fmt("--timestamp={d}", .{timestamp});
 
     for (headers_to_generate) |header_info| {
@@ -265,9 +319,7 @@ pub fn generateApi(b: *std.Build, parser_exe: *std.Build.Step.Compile, fetch_sdl
         if (basedir) |dir| {
             regenerate.addArg(b.fmt("--basedir={s}", .{dir}));
         }
-        if (c_import_path) |path| {
-            regenerate.addArg(b.fmt("--c-import={s}", .{path}));
-        }
+        regenerate.addArg(b.fmt("--c-import={s}", .{effective_c_import_path}));
         // regenerate.addArg(b.fmt("--output=api/{s}.zig --mocks=mocks/{s}.c", .{ header_info.output, header_info.output }));
         regenerate.step.dependOn(path_prep_step);
         regenerate_step.dependOn(&regenerate.step);
diff --git a/src/codegen.zig b/src/codegen.zig
index 00f2850..87c144c 100644
--- a/src/codegen.zig
+++ b/src/codegen.zig
@@ -26,12 +26,14 @@ pub const CodeGenOptions = struct {
     decls: []const ResolvedDecl,
     module_name: []const u8,
     c_import_path: []const u8 = "c.zig",
+    skipped: []const patterns.SkippedDecl = &.{},
 };
 
 pub const CodeGen = struct {
     decls: []const ResolvedDecl,
     module_name: []const u8,
     c_import_path: []const u8,
+    skipped: []const patterns.SkippedDecl,
     allocator: Allocator,
     output: std.ArrayList(u8),
     opaque_methods: std.StringHashMap(std.ArrayList(patterns.FunctionDecl)),
@@ -43,6 +45,7 @@ pub const CodeGen = struct {
             .decls = options.decls,
             .module_name = options.module_name,
             .c_import_path = options.c_import_path,
+            .skipped = options.skipped,
             .allocator = allocator,
             .output = try std.ArrayList(u8).initCapacity(allocator, 4096),
             .opaque_methods = std.StringHashMap(std.ArrayList(patterns.FunctionDecl)).init(allocator),
@@ -200,6 +203,14 @@ pub const CodeGen = struct {
         if (self.aliases.items.len > 0) {
             try self.output.appendSlice(self.allocator, "\n");
         }
+
+        if (self.skipped.len > 0) {
+            try self.output.appendSlice(self.allocator, "pub const unsupported = struct {\n");
+            for (self.skipped) |item| {
+                try self.output.writer(self.allocator).print("    pub const @\"{s}\" = \"{s}\";\n", .{ item.name, item.reason });
+            }
+            try self.output.appendSlice(self.allocator, "};\n\n");
+        }
     }
 
     fn writeDeclarations(self: *CodeGen) !void {
@@ -446,7 +457,7 @@ pub const CodeGen = struct {
 
         try self.output.writer(self.allocator).print("pub const {s} = extern struct {{\n", .{zig_name});
         for (struct_decl.fields) |field| {
-            const zig_type = try types.convertType(field.type_name, self.allocator);
+            const zig_type = try self.convertAggregateFieldType(field.type_name);
             defer self.allocator.free(zig_type);
             if (field.comment) |comment| {
                 try self.output.writer(self.allocator).print("    {s}: {s}, // {s}\n", .{ field.name, zig_type, comment });
@@ -462,7 +473,7 @@ pub const CodeGen = struct {
         if (union_decl.doc_comment) |doc| try self.writeDocComment(doc);
         try self.output.writer(self.allocator).print("pub const {s} = extern union {{\n", .{zig_name});
         for (union_decl.fields) |field| {
-            const zig_type = try types.convertType(field.type_name, self.allocator);
+            const zig_type = try self.convertAggregateFieldType(field.type_name);
             defer self.allocator.free(zig_type);
             if (field.comment) |comment| {
                 try self.output.writer(self.allocator).print("    {s}: {s}, // {s}\n", .{ field.name, zig_type, comment });
@@ -550,7 +561,7 @@ pub const CodeGen = struct {
 
         try self.output.writer(self.allocator).print("    pub inline fn {s}(", .{zig_name});
         for (func.params, 0..) |param, i| {
-            const zig_type = try types.convertType(param.type_name, self.allocator);
+            const zig_type = try self.convertFunctionParamType(func, param);
             defer self.allocator.free(zig_type);
             if (i > 0) try self.output.appendSlice(self.allocator, ", ");
 
@@ -568,7 +579,7 @@ pub const CodeGen = struct {
         try self.output.writer(self.allocator).print(") {s} {{\n", .{zig_return_type});
         try self.output.appendSlice(self.allocator, "        return ");
 
-        const return_cast = if (!std.mem.eql(u8, zig_return_type, "void")) types.getCastType(zig_return_type) else .none;
+        const return_cast = if (!std.mem.eql(u8, zig_return_type, "void")) types.getReturnCastType(zig_return_type) else .none;
         if (return_cast != .none) {
             try self.output.writer(self.allocator).print("{s}(", .{castTypeToString(return_cast)});
         }
@@ -584,9 +595,9 @@ pub const CodeGen = struct {
                 } else try self.allocator.dupe(u8, param.name);
                 defer self.allocator.free(param_name);
 
-                const zig_param_type = try types.convertType(param.type_name, self.allocator);
+                const zig_param_type = try self.convertFunctionParamType(func, param);
                 defer self.allocator.free(zig_param_type);
-                const param_cast = types.getCastType(zig_param_type);
+                const param_cast = self.getFunctionParamCastType(param, zig_param_type);
 
                 if (param_cast == .none) {
                     try self.output.writer(self.allocator).print("{s}", .{param_name});
@@ -614,7 +625,7 @@ pub const CodeGen = struct {
         try self.output.writer(self.allocator).print("pub inline fn {s}(", .{zig_name});
 
         for (func.params, 0..) |param, i| {
-            const zig_type = try types.convertType(param.type_name, self.allocator);
+            const zig_type = try self.convertFunctionParamType(func, param);
             defer self.allocator.free(zig_type);
             if (i > 0) try self.output.appendSlice(self.allocator, ", ");
             if (param.name.len > 0) {
@@ -626,7 +637,7 @@ pub const CodeGen = struct {
         try self.output.writer(self.allocator).print(") {s} {{\n", .{zig_return_type});
         try self.output.appendSlice(self.allocator, "    return ");
 
-        const return_cast = if (!std.mem.eql(u8, zig_return_type, "void")) types.getCastType(zig_return_type) else .none;
+        const return_cast = if (!std.mem.eql(u8, zig_return_type, "void")) types.getReturnCastType(zig_return_type) else .none;
         if (return_cast != .none) {
             try self.output.writer(self.allocator).print("{s}(", .{castTypeToString(return_cast)});
         }
@@ -635,9 +646,9 @@ pub const CodeGen = struct {
         for (func.params, 0..) |param, i| {
             if (i > 0) try self.output.appendSlice(self.allocator, ", ");
             if (param.name.len > 0) {
-                const zig_param_type = try types.convertType(param.type_name, self.allocator);
+                const zig_param_type = try self.convertFunctionParamType(func, param);
                 defer self.allocator.free(zig_param_type);
-                const param_cast = types.getCastType(zig_param_type);
+                const param_cast = self.getFunctionParamCastType(param, zig_param_type);
 
                 if (param_cast == .none) {
                     try self.output.writer(self.allocator).print("{s}", .{param.name});
@@ -655,6 +666,118 @@ pub const CodeGen = struct {
         try self.output.appendSlice(self.allocator, "}\n\n");
     }
 
+    fn convertAggregateFieldType(self: *CodeGen, c_type: []const u8) ![]const u8 {
+        if (self.isOpaqueFieldPointerType(c_type)) {
+            return try types.convertType(c_type, self.allocator);
+        }
+        return try types.convertStructFieldType(c_type, self.allocator);
+    }
+
+    fn convertFunctionParamType(self: *CodeGen, func: patterns.FunctionDecl, param: patterns.ParamDecl) ![]const u8 {
+        const zig_type = try types.convertType(param.type_name, self.allocator);
+        errdefer self.allocator.free(zig_type);
+
+        if (std.mem.startsWith(u8, zig_type, "?*") or std.mem.startsWith(u8, zig_type, "[*c]")) {
+            return zig_type;
+        }
+
+        const should_make_nullable =
+            self.paramMayBeNull(func, param.name) or
+            (std.mem.startsWith(u8, zig_type, "*") and !std.mem.startsWith(u8, zig_type, "*const "));
+
+        if (should_make_nullable and std.mem.startsWith(u8, zig_type, "*")) {
+            const nullable = try std.fmt.allocPrint(self.allocator, "?{s}", .{zig_type});
+            self.allocator.free(zig_type);
+            return nullable;
+        }
+
+        return zig_type;
+    }
+
+    fn getFunctionParamCastType(self: *CodeGen, param: patterns.ParamDecl, zig_param_type: []const u8) types.CastType {
+        if (self.isSDLPointerArrayParam(param.type_name)) {
+            return .ptr_cast;
+        }
+        return types.getParamCastType(zig_param_type);
+    }
+
+    fn paramMayBeNull(self: *CodeGen, func: patterns.FunctionDecl, param_name: []const u8) bool {
+        _ = self;
+        if (param_name.len == 0) return false;
+        const doc = func.doc_comment orelse return false;
+
+        const marker = std.fmt.allocPrint(std.heap.smp_allocator, "\\param {s}", .{param_name}) catch return false;
+        defer std.heap.smp_allocator.free(marker);
+
+        const start = std.mem.indexOf(u8, doc, marker) orelse return false;
+        const tail = doc[start + marker.len ..];
+        const next_param = std.mem.indexOf(u8, tail, "\\param ") orelse tail.len;
+        const next_returns = std.mem.indexOf(u8, tail, "\\returns") orelse tail.len;
+        const end = @min(next_param, next_returns);
+        const param_doc = tail[0..end];
+
+        return std.mem.indexOf(u8, param_doc, "may be NULL") != null or
+            std.mem.indexOf(u8, param_doc, "or NULL") != null;
+    }
+
+    fn isOpaqueFieldPointerType(self: *CodeGen, c_type: []const u8) bool {
+        const trimmed = std.mem.trim(u8, c_type, " \t");
+        if (std.mem.indexOf(u8, trimmed, "(SDLCALL *") != null or std.mem.indexOf(u8, trimmed, "(*") != null) {
+            return false;
+        }
+        if (std.mem.indexOfScalar(u8, trimmed, '*') == null) {
+            return false;
+        }
+
+        var rest = trimmed;
+        if (std.mem.startsWith(u8, rest, "const ")) {
+            rest = std.mem.trim(u8, rest[6..], " \t");
+        }
+
+        const first_star = std.mem.indexOfScalar(u8, rest, '*') orelse return false;
+        const base_type = std.mem.trim(u8, rest[0..first_star], " \t");
+        if (!std.mem.startsWith(u8, base_type, "SDL_")) {
+            return false;
+        }
+
+        const zig_name = naming.typeNameToZig(base_type);
+        if (self.opaque_methods.contains(zig_name)) {
+            return true;
+        }
+
+        for (self.decls) |resolved| {
+            if (resolved.decl != .opaque_type) continue;
+            if (std.mem.eql(u8, resolved.decl.opaque_type.name, base_type)) {
+                return true;
+            }
+            if (std.mem.eql(u8, naming.typeNameToZig(resolved.decl.opaque_type.name), zig_name)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    fn isSDLPointerArrayParam(self: *CodeGen, c_type: []const u8) bool {
+        _ = self;
+        const trimmed = std.mem.trim(u8, c_type, " \t");
+        if (std.mem.indexOf(u8, trimmed, "(SDLCALL *") != null or std.mem.indexOf(u8, trimmed, "(*") != null) {
+            return false;
+        }
+        if (std.mem.count(u8, trimmed, "*") < 2) {
+            return false;
+        }
+
+        var rest = trimmed;
+        if (std.mem.startsWith(u8, rest, "const ")) {
+            rest = std.mem.trim(u8, rest[6..], " \t");
+        }
+
+        const first_star = std.mem.indexOfScalar(u8, rest, '*') orelse return false;
+        const base_type = std.mem.trim(u8, rest[0..first_star], " \t");
+        return std.mem.startsWith(u8, base_type, "SDL_");
+    }
+
     fn castTypeToString(cast_type: types.CastType) []const u8 {
         return switch (cast_type) {
             .none => "none",
@@ -775,3 +898,93 @@ test "primary declarations are emitted without self imports" {
     try std.testing.expect(std.mem.indexOf(u8, output, "const video_api = @import(\"video.zig\");") == null);
     try std.testing.expect(std.mem.indexOf(u8, output, "pub const Window = opaque") != null);
 }
+
+test "function params make plain out pointers nullable" {
+    const allocator = std.testing.allocator;
+    var gen = CodeGen{
+        .decls = &.{},
+        .module_name = "gpu",
+        .c_import_path = "c.zig",
+        .skipped = &.{},
+        .allocator = allocator,
+        .output = .empty,
+        .opaque_methods = std.StringHashMap(std.ArrayList(patterns.FunctionDecl)).init(allocator),
+        .import_modules = .empty,
+        .aliases = .empty,
+    };
+    defer gen.deinit();
+
+    var params = [_]patterns.ParamDecl{
+        .{ .name = "swapchain_texture_width", .type_name = "Uint32 *" },
+    };
+    const func = patterns.FunctionDecl{
+        .name = "SDL_WaitAndAcquireGPUSwapchainTexture",
+        .return_type = "bool",
+        .params = params[0..],
+        .doc_comment = null,
+    };
+
+    const zig_type = try gen.convertFunctionParamType(func, params[0]);
+    defer allocator.free(zig_type);
+    try std.testing.expectEqualStrings("?*u32", zig_type);
+}
+
+test "opaque methods cast enum params to C ABI" {
+    const allocator = std.testing.allocator;
+
+    var decls: std.ArrayList(ResolvedDecl) = .empty;
+    defer {
+        for (decls.items) |decl| decl.deinit(allocator);
+        decls.deinit(allocator);
+    }
+
+    try decls.append(allocator, .{
+        .decl = .{ .opaque_type = .{ .name = try allocator.dupe(u8, "SDL_GPURenderPass"), .doc_comment = null } },
+        .source_header = try allocator.dupe(u8, "SDL_gpu.h"),
+        .is_primary_header_decl = true,
+    });
+    try decls.append(allocator, .{
+        .decl = .{ .struct_decl = .{
+            .name = try allocator.dupe(u8, "SDL_GPUBufferBinding"),
+            .fields = &.{},
+            .doc_comment = null,
+            .has_unions = false,
+        } },
+        .source_header = try allocator.dupe(u8, "SDL_gpu.h"),
+        .is_primary_header_decl = true,
+    });
+    const enum_values = try allocator.alloc(patterns.EnumValue, 1);
+    enum_values[0] = .{ .name = try allocator.dupe(u8, "SDL_GPU_INDEXELEMENTSIZE_16BIT"), .value = null, .comment = null };
+    try decls.append(allocator, .{
+        .decl = .{ .enum_decl = .{
+            .name = try allocator.dupe(u8, "SDL_GPUIndexElementSize"),
+            .values = enum_values,
+            .doc_comment = null,
+        } },
+        .source_header = try allocator.dupe(u8, "SDL_gpu.h"),
+        .is_primary_header_decl = true,
+    });
+    const func_params = try allocator.alloc(patterns.ParamDecl, 3);
+    func_params[0] = .{ .name = try allocator.dupe(u8, "render_pass"), .type_name = try allocator.dupe(u8, "SDL_GPURenderPass *") };
+    func_params[1] = .{ .name = try allocator.dupe(u8, "binding"), .type_name = try allocator.dupe(u8, "const SDL_GPUBufferBinding *") };
+    func_params[2] = .{ .name = try allocator.dupe(u8, "index_element_size"), .type_name = try allocator.dupe(u8, "SDL_GPUIndexElementSize") };
+    try decls.append(allocator, .{
+        .decl = .{ .function_decl = .{
+            .name = try allocator.dupe(u8, "SDL_BindGPUIndexBuffer"),
+            .return_type = try allocator.dupe(u8, "void"),
+            .params = func_params,
+            .doc_comment = null,
+        } },
+        .source_header = try allocator.dupe(u8, "SDL_gpu.h"),
+        .is_primary_header_decl = true,
+    });
+
+    const output = try CodeGen.generate(allocator, .{
+        .decls = decls.items,
+        .module_name = "gpu",
+        .c_import_path = "../c.zig",
+    });
+    defer allocator.free(output);
+
+    try std.testing.expect(std.mem.indexOf(u8, output, "@intFromEnum(index_element_size)") != null);
+}
diff --git a/src/parser.zig b/src/parser.zig
index dec3ff1..e3abd22 100644
--- a/src/parser.zig
+++ b/src/parser.zig
@@ -85,10 +85,21 @@ pub fn main() !void {
 
     // Parse declarations
     var scanner = patterns.Scanner.init(allocator, source);
+    defer scanner.deinit();
     const decls = try scanner.scan();
     defer freeDecls(allocator, decls);
+    const skipped = try scanner.takeSkipped();
+    defer {
+        for (skipped) |item| {
+            item.deinit(allocator);
+        }
+        allocator.free(skipped);
+    }
 
     std.debug.print("Found {d} declarations\n", .{decls.len});
+    if (skipped.len > 0) {
+        std.debug.print("Skipped {d} unsupported declarations\n", .{skipped.len});
+    }
 
     // Count each type
     var opaque_count: usize = 0;
@@ -281,6 +292,7 @@ pub fn main() !void {
         .decls = all_resolved_decls.items,
         .module_name = module_name,
         .c_import_path = c_import_path,
+        .skipped = skipped,
     });
     defer allocator.free(output);
 
diff --git a/src/patterns.zig b/src/patterns.zig
index a57c31c..381b827 100644
--- a/src/patterns.zig
+++ b/src/patterns.zig
@@ -202,11 +202,22 @@ pub const ParamDecl = struct {
     type_name: []const u8, // SDL_GPUShaderFormat
 };
 
+pub const SkippedDecl = struct {
+    name: []const u8,
+    reason: []const u8,
+
+    pub fn deinit(self: SkippedDecl, allocator: Allocator) void {
+        allocator.free(self.name);
+        allocator.free(self.reason);
+    }
+};
+
 pub const Scanner = struct {
     source: []const u8,
     pos: usize,
     allocator: Allocator,
     pending_doc_comment: ?[]const u8,
+    skipped: std.ArrayList(SkippedDecl),
 
     pub fn init(allocator: Allocator, source: []const u8) Scanner {
         return .{
@@ -214,9 +225,17 @@ pub const Scanner = struct {
             .pos = 0,
             .allocator = allocator,
             .pending_doc_comment = null,
+            .skipped = .empty,
         };
     }
 
+    pub fn deinit(self: *Scanner) void {
+        for (self.skipped.items) |item| {
+            item.deinit(self.allocator);
+        }
+        self.skipped.deinit(self.allocator);
+    }
+
     pub fn scan(self: *Scanner) ![]Declaration {
         var decls = try std.ArrayList(Declaration).initCapacity(self.allocator, 100);
 
@@ -226,6 +245,10 @@ pub const Scanner = struct {
                 self.pending_doc_comment = comment;
             }
 
+            if (try self.scanUnsupportedMacro()) {
+                continue;
+            }
+
             // Try each pattern - order matters!
             // Try opaque first (typedef struct SDL_X SDL_X;)
             if (try self.scanOpaque()) |opaque_decl| {
@@ -260,6 +283,50 @@ pub const Scanner = struct {
         return try decls.toOwnedSlice(self.allocator);
     }
 
+    pub fn takeSkipped(self: *Scanner) ![]SkippedDecl {
+        const items = try self.skipped.toOwnedSlice(self.allocator);
+        self.skipped = .empty;
+        return items;
+    }
+
+    fn recordSkippedDecl(self: *Scanner, name: []const u8, reason: []const u8) !void {
+        try self.skipped.append(self.allocator, .{
+            .name = try self.allocator.dupe(u8, name),
+            .reason = try self.allocator.dupe(u8, reason),
+        });
+    }
+
+    fn scanUnsupportedMacro(self: *Scanner) !bool {
+        if (!std.mem.startsWith(u8, self.source[self.pos..], "#define ")) {
+            return false;
+        }
+
+        const start = self.pos;
+        const line = try self.readLine();
+        defer self.allocator.free(line);
+
+        var parts = std.mem.tokenizeScalar(u8, line, ' ');
+        const define_name = parts.next() orelse {
+            self.pos = start;
+            return false;
+        };
+
+        if (std.mem.indexOfScalar(u8, define_name, '(') == null) {
+            self.pos = start;
+            return false;
+        }
+
+        const macro_name = define_name[0 .. std.mem.indexOfScalar(u8, define_name, '(').?];
+        try self.recordSkippedDecl(macro_name, "function-like macro is not emitted");
+
+        if (self.pending_doc_comment) |comment| {
+            self.allocator.free(comment);
+            self.pending_doc_comment = null;
+        }
+
+        return true;
+    }
+
     // Pattern: typedef struct SDL_Foo SDL_Foo;
     fn scanOpaque(self: *Scanner) !?OpaqueType {
         const start = self.pos;
@@ -1692,6 +1759,15 @@ pub const Scanner = struct {
         for (vararg_macros) |macro| {
             if (std.mem.indexOf(u8, text, macro)) |pos| {
                 _ = pos;
+                if (std.mem.indexOf(u8, text, "SDLCALL ")) |sdlcall_pos| {
+                    const after_sdlcall = text[sdlcall_pos + 8 ..];
+                    if (std.mem.indexOfScalar(u8, after_sdlcall, '(')) |paren_pos| {
+                        const func_name = std.mem.trim(u8, after_sdlcall[0..paren_pos], " \t\n*");
+                        if (func_name.len > 0) {
+                            try self.recordSkippedDecl(func_name, "varargs function is not representable in Zig");
+                        }
+                    }
+                }
                 return null; // we dont attempt to generate vararg functions.
             }
         }
diff --git a/src/types.zig b/src/types.zig
index 855921a..e61450d 100644
--- a/src/types.zig
+++ b/src/types.zig
@@ -1,11 +1,8 @@
 const std = @import("std");
 const Allocator = std.mem.Allocator;
-const io = @import("io");
-
-var fmtBuffer: [256]u8 = undefined;
 /// Convert C type to Zig type
 /// Simple table-based conversion for SDL3 types
-pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
+pub fn convertType(c_type: []const u8, allocator: Allocator) Allocator.Error![]const u8 {
     const trimmed = std.mem.trim(u8, c_type, " \t");
 
     // Handle opaque struct pointers: "struct X *" -> "*anyopaque"
@@ -13,17 +10,17 @@ pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
         return try allocator.dupe(u8, "*anyopaque");
     }
 
-    // Handle function pointers: For now, just return as placeholder until we implement full conversion
+    // Handle function pointers used in callbacks and interface structs.
     if (std.mem.indexOf(u8, trimmed, "(SDLCALL *") != null or std.mem.indexOf(u8, trimmed, "(*") != null) {
-        // TODO: Implement full function pointer conversion
-        // For now, return a placeholder type
-        return try std.fmt.allocPrint(allocator, "?*const anyopaque", .{});
+        return try convertFunctionPointerType(trimmed, allocator);
     }
 
     // Handle array types: "Uint8[2]" -> "[2]u8"
     if (std.mem.indexOf(u8, trimmed, "[")) |bracket_pos| {
         const base_type = std.mem.trim(u8, trimmed[0..bracket_pos], " \t");
         var array_part = trimmed[bracket_pos..]; // "[2]"
+        var owned_array_part: ?[]const u8 = null;
+        defer if (owned_array_part) |slice| allocator.free(slice);
 
         // Recursively convert the base type
         const zig_base = try convertType(base_type, allocator);
@@ -39,13 +36,8 @@ pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
             };
 
             if (alias_to_c) {
-                var b = std.io.fixedBufferStream(&fmtBuffer);
-                _ = try b.write("[");
-                _ = try b.write("c.");
-                _ = try b.write(inner);
-                _ = try b.write("]");
-                array_part = b.getWritten();
-                std.debug.print("arrya_part = {s}\n", .{array_part});
+                owned_array_part = try std.fmt.allocPrint(allocator, "[c.{s}]", .{inner});
+                array_part = owned_array_part.?;
             }
         }
 
@@ -97,12 +89,12 @@ pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
         // Match "SDL_Type *const *" (no space before const)
         if (std.mem.indexOf(u8, trimmed, " *const *")) |pos| {
             const base_type = trimmed[4..pos]; // Remove SDL_ prefix and get type
-            return std.fmt.allocPrint(allocator, "[*c]?*const {s}", .{base_type});
+            return std.fmt.allocPrint(allocator, "[*c]const ?*{s}", .{base_type});
         }
         // Match "SDL_Type * const *" (space before const)
         if (std.mem.indexOf(u8, trimmed, " * const *")) |pos| {
             const base_type = trimmed[4..pos]; // Remove SDL_ prefix and get type
-            return std.fmt.allocPrint(allocator, "[*c]?*const {s}", .{base_type});
+            return std.fmt.allocPrint(allocator, "[*c]const ?*{s}", .{base_type});
         }
         if (std.mem.indexOf(u8, trimmed, " **")) |pos| {
             const base_type = trimmed[4..pos]; // Remove SDL_ prefix and get type
@@ -127,11 +119,23 @@ pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
     if (std.mem.eql(u8, trimmed, "Sint8 *")) return try allocator.dupe(u8, "*i8");
     if (std.mem.eql(u8, trimmed, "Sint16 *")) return try allocator.dupe(u8, "*i16");
     if (std.mem.eql(u8, trimmed, "Sint32 *")) return try allocator.dupe(u8, "*i32");
+    if (std.mem.eql(u8, trimmed, "Sint64 *")) return try allocator.dupe(u8, "*i64");
+    if (std.mem.eql(u8, trimmed, "const Sint64 *")) return try allocator.dupe(u8, "*const i64");
     if (std.mem.eql(u8, trimmed, "const bool *")) return try allocator.dupe(u8, "*const bool");
 
     if (std.mem.startsWith(u8, trimmed, "const ")) {
         const rest = trimmed[6..];
         if (std.mem.startsWith(u8, rest, "SDL_")) {
+            if (std.mem.indexOf(u8, rest, " *const *")) |pos| {
+                const base_type = rest[0..pos];
+                const zig_type = base_type[4..];
+                return std.fmt.allocPrint(allocator, "[*c]const ?*const {s}", .{zig_type});
+            }
+            if (std.mem.indexOf(u8, rest, " * const *")) |pos| {
+                const base_type = rest[0..pos];
+                const zig_type = base_type[4..];
+                return std.fmt.allocPrint(allocator, "[*c]const ?*const {s}", .{zig_type});
+            }
             if (std.mem.indexOfScalar(u8, rest, '*')) |star_pos| {
                 const base_type = std.mem.trim(u8, rest[0..star_pos], " \t");
                 const star_count = std.mem.count(u8, rest[star_pos..], "*");
@@ -152,20 +156,6 @@ pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
                 return std.fmt.allocPrint(allocator, "[*c]?*const {s}", .{zig_type});
             }
         }
-        if (std.mem.indexOf(u8, rest, " *const *")) |pos| {
-            const base_type = rest[0..pos];
-            if (std.mem.startsWith(u8, base_type, "SDL_")) {
-                const zig_type = base_type[4..];
-                return std.fmt.allocPrint(allocator, "[*c]?*const {s}", .{zig_type});
-            }
-        }
-        if (std.mem.indexOf(u8, rest, " * const *")) |pos| {
-            const base_type = rest[0..pos];
-            if (std.mem.startsWith(u8, base_type, "SDL_")) {
-                const zig_type = base_type[4..];
-                return std.fmt.allocPrint(allocator, "[*c]?*const {s}", .{zig_type});
-            }
-        }
         if (std.mem.endsWith(u8, rest, " *") or std.mem.endsWith(u8, rest, "*")) {
             const base_type = if (std.mem.endsWith(u8, rest, " *"))
                 rest[0 .. rest.len - 2]
@@ -220,39 +210,121 @@ pub fn convertType(c_type: []const u8, allocator: Allocator) ![]const u8 {
     return try allocator.dupe(u8, trimmed);
 }
 
-/// Determine the appropriate cast for a given type when calling C functions
-pub fn getCastType(zig_type: []const u8) CastType {
+pub fn convertStructFieldType(c_type: []const u8, allocator: Allocator) Allocator.Error![]const u8 {
+    const trimmed = std.mem.trim(u8, c_type, " \t");
+
+    if (std.mem.indexOf(u8, trimmed, "(SDLCALL *") != null or std.mem.indexOf(u8, trimmed, "(*") != null) {
+        return try convertType(trimmed, allocator);
+    }
+
+    if (std.mem.indexOfScalar(u8, trimmed, '[') != null) {
+        return try convertType(trimmed, allocator);
+    }
+
+    if (std.mem.indexOfScalar(u8, trimmed, '*') == null) {
+        return try convertType(trimmed, allocator);
+    }
+
+    var rest = trimmed;
+    var pointee_const = false;
+    if (std.mem.startsWith(u8, rest, "const ")) {
+        pointee_const = true;
+        rest = std.mem.trim(u8, rest[6..], " \t");
+    }
+
+    const first_star = std.mem.indexOfScalar(u8, rest, '*') orelse return try convertType(trimmed, allocator);
+    const base_type = std.mem.trim(u8, rest[0..first_star], " \t");
+    const star_count = std.mem.count(u8, rest[first_star..], "*");
+
+    const zig_base = if (std.mem.eql(u8, base_type, "void"))
+        try allocator.dupe(u8, "anyopaque")
+    else
+        try convertType(base_type, allocator);
+    defer allocator.free(zig_base);
+
+    var result: std.ArrayList(u8) = .empty;
+    defer result.deinit(allocator);
+
+    for (0..star_count) |_| {
+        try result.appendSlice(allocator, "[*c]");
+    }
+    if (pointee_const) {
+        try result.appendSlice(allocator, "const ");
+    }
+    try result.appendSlice(allocator, zig_base);
+
+    return try result.toOwnedSlice(allocator);
+}
+
+fn isOpaquePointerLike(zig_type: []const u8) bool {
+    if (!(std.mem.startsWith(u8, zig_type, "?*") or std.mem.startsWith(u8, zig_type, "*"))) {
+        return false;
+    }
+
+    if (std.mem.indexOf(u8, zig_type, "anyopaque") != null or
+        std.mem.startsWith(u8, zig_type, "[*c]") or
+        std.mem.startsWith(u8, zig_type, "?[*c]"))
+    {
+        return false;
+    }
+
+    return true;
+}
+
+fn isEnumLikeType(zig_type: []const u8) bool {
+    if (isPackedFlagsLikeType(zig_type)) return false;
+
+    return std.mem.indexOf(u8, zig_type, "Type") != null or
+        std.mem.indexOf(u8, zig_type, "Size") != null or
+        std.mem.indexOf(u8, zig_type, "Mode") != null or
+        std.mem.indexOf(u8, zig_type, "Op") != null or
+        std.mem.endsWith(u8, zig_type, "Format");
+}
+
+fn isPackedFlagsLikeType(zig_type: []const u8) bool {
+    return std.mem.endsWith(u8, zig_type, "Flags") or
+        std.mem.eql(u8, zig_type, "GPUShaderFormat") or
+        std.mem.eql(u8, zig_type, "FlipMode");
+}
+
+/// Determine the appropriate cast for a Zig parameter passed into a C function.
+pub fn getParamCastType(zig_type: []const u8) CastType {
     // Bool needs @bitCast
     if (std.mem.eql(u8, zig_type, "bool")) {
         return .bit_cast;
     }
 
     // Opaque pointers need @ptrCast (both ?*Type and *Type)
-    // Skip [*c] (C pointers) and *anyopaque
-    if (std.mem.startsWith(u8, zig_type, "?*") or std.mem.startsWith(u8, zig_type, "*")) {
-        // Exclude anyopaque and C pointers
-        if (std.mem.indexOf(u8, zig_type, "anyopaque") != null or 
-            std.mem.startsWith(u8, zig_type, "[*c]") or
-            std.mem.startsWith(u8, zig_type, "?[*c]")) {
-            return .none;
-        }
+    if (isOpaquePointerLike(zig_type)) {
         return .ptr_cast;
     }
 
-    // Enums need @intFromEnum
-    // We'll detect these by naming convention or explicit marking
-    // For now, assume types ending in certain patterns are enums
-    if (std.mem.indexOf(u8, zig_type, "Type") != null or
-        std.mem.indexOf(u8, zig_type, "Mode") != null or
-        std.mem.indexOf(u8, zig_type, "Op") != null)
-    {
+    if (isEnumLikeType(zig_type)) {
         return .int_from_enum;
     }
 
-    // Flags (packed structs) need @bitCast
-    if (std.mem.endsWith(u8, zig_type, "Flags") or
-        std.mem.endsWith(u8, zig_type, "Format"))
-    {
+    if (isPackedFlagsLikeType(zig_type)) {
+        return .bit_cast;
+    }
+
+    return .none;
+}
+
+/// Determine the appropriate cast for a C return value exposed as a Zig type.
+pub fn getReturnCastType(zig_type: []const u8) CastType {
+    if (std.mem.eql(u8, zig_type, "bool")) {
+        return .bit_cast;
+    }
+
+    if (isOpaquePointerLike(zig_type)) {
+        return .ptr_cast;
+    }
+
+    if (isEnumLikeType(zig_type)) {
+        return .enum_from_int;
+    }
+
+    if (isPackedFlagsLikeType(zig_type)) {
         return .bit_cast;
     }
 
@@ -261,7 +333,7 @@ pub fn getCastType(zig_type: []const u8) CastType {
 
 /// Convert C function pointer type to Zig function pointer syntax
 /// Example: Sint64 (SDLCALL *size)(void *userdata) -> *const fn (?*anyopaque) callconv(.C) i64
-fn convertFunctionPointerType(c_type: []const u8, allocator: Allocator) ![]const u8 {
+fn convertFunctionPointerType(c_type: []const u8, allocator: Allocator) Allocator.Error![]const u8 {
     // Pattern: ReturnType (SDLCALL *name)(params) or ReturnType (*name)(params)
 
     // Find the return type (everything before the opening paren)
@@ -284,12 +356,12 @@ fn convertFunctionPointerType(c_type: []const u8, allocator: Allocator) ![]const
     defer allocator.free(zig_return);
 
     // Convert parameters
-    var params_list = std.ArrayList([]const u8).init(allocator);
+    var params_list: std.ArrayList([]const u8) = .empty;
     defer {
         for (params_list.items) |param| {
             allocator.free(param);
         }
-        params_list.deinit();
+        params_list.deinit(allocator);
     }
 
     // Parse comma-separated parameters
@@ -298,43 +370,53 @@ fn convertFunctionPointerType(c_type: []const u8, allocator: Allocator) ![]const
         const trimmed_param = std.mem.trim(u8, param, " \t");
         if (trimmed_param.len == 0) continue;
 
-        // Extract just the type (remove parameter name if present)
-        // Pattern: "void *userdata" -> "void *"
-        // Pattern: "Sint64 offset" -> "Sint64"
-        var param_type: []const u8 = trimmed_param;
-
-        // Find the last space that separates type from name
-        if (std.mem.lastIndexOf(u8, trimmed_param, " ")) |space_pos| {
-            // Check if what comes after is an identifier (not a *)
-            const after_space = trimmed_param[space_pos + 1 ..];
-            if (after_space.len > 0 and after_space[0] != '*') {
-                param_type = std.mem.trimRight(u8, trimmed_param[0..space_pos], " \t");
-            }
-        }
+        const param_type = stripParamName(trimmed_param);
 
         // Don't recursively convert function pointers in params
         const zig_param = if (std.mem.indexOf(u8, param_type, "(") != null)
             try allocator.dupe(u8, param_type)
         else
             try convertType(param_type, allocator);
-        try params_list.append(zig_param);
+        try params_list.append(allocator, zig_param);
     }
 
     // Build Zig function pointer type
-    var result = std.ArrayList(u8).init(allocator);
-    defer result.deinit();
+    var result: std.ArrayList(u8) = .empty;
+    defer result.deinit(allocator);
 
-    try result.appendSlice("?*const fn (");
+    try result.appendSlice(allocator, "?*const fn(");
 
     for (params_list.items, 0..) |param, i| {
-        if (i > 0) try result.appendSlice(", ");
-        try result.appendSlice(param);
+        if (i > 0) try result.appendSlice(allocator, ", ");
+        try result.appendSlice(allocator, param);
     }
 
-    try result.appendSlice(") callconv(.C) ");
-    try result.appendSlice(zig_return);
+    try result.appendSlice(allocator, ") callconv(.C) ");
+    try result.appendSlice(allocator, zig_return);
 
-    return try result.toOwnedSlice();
+    return try result.toOwnedSlice(allocator);
+}
+
+fn stripParamName(param: []const u8) []const u8 {
+    if (param.len == 0) return param;
+    if (std.mem.eql(u8, param, "...")) return param;
+
+    var ident_start = param.len;
+    while (ident_start > 0) {
+        const c = param[ident_start - 1];
+        if (std.ascii.isAlphanumeric(c) or c == '_') {
+            ident_start -= 1;
+            continue;
+        }
+        break;
+    }
+
+    if (ident_start == param.len or ident_start == 0) return param;
+
+    const before_name = std.mem.trimRight(u8, param[0..ident_start], " \t");
+    if (before_name.len == 0) return param;
+
+    return before_name;
 }
 
 pub const CastType = enum {
@@ -352,3 +434,46 @@ test "convert const SDL double pointer" {
 
     try std.testing.expectEqualStrings("[*c]?*const TrayEntry", zig_type);
 }
+
+test "convert function pointer callback type" {
+    const allocator = std.testing.allocator;
+    const zig_type = try convertType("Sint64 (SDLCALL *size)(void *userdata)", allocator);
+    defer allocator.free(zig_type);
+
+    try std.testing.expectEqualStrings("?*const fn(?*anyopaque) callconv(.C) i64", zig_type);
+}
+
+test "convert SDL pointer arrays preserves const on outer sequence" {
+    const allocator = std.testing.allocator;
+
+    const zig_type = try convertType("SDL_GPUBuffer *const *", allocator);
+    defer allocator.free(zig_type);
+    try std.testing.expectEqualStrings("[*c]const ?*GPUBuffer", zig_type);
+
+    const const_zig_type = try convertType("const SDL_GPUBuffer *const *", allocator);
+    defer allocator.free(const_zig_type);
+    try std.testing.expectEqualStrings("[*c]const ?*const GPUBuffer", const_zig_type);
+}
+
+test "enum cast direction differs for params and returns" {
+    try std.testing.expectEqual(.int_from_enum, getParamCastType("GPUTextureFormat"));
+    try std.testing.expectEqual(.enum_from_int, getReturnCastType("GPUTextureFormat"));
+    try std.testing.expectEqual(.int_from_enum, getParamCastType("GPUIndexElementSize"));
+    try std.testing.expectEqual(.enum_from_int, getReturnCastType("GPUIndexElementSize"));
+    try std.testing.expectEqual(.bit_cast, getParamCastType("GPUShaderFormat"));
+    try std.testing.expectEqual(.bit_cast, getReturnCastType("GPUShaderFormat"));
+    try std.testing.expectEqual(.bit_cast, getParamCastType("FlipMode"));
+    try std.testing.expectEqual(.bit_cast, getReturnCastType("FlipMode"));
+}
+
+test "struct fields use C pointers" {
+    const allocator = std.testing.allocator;
+
+    const single = try convertStructFieldType("const SDL_GPUColorTargetDescription *", allocator);
+    defer allocator.free(single);
+    try std.testing.expectEqualStrings("[*c]const GPUColorTargetDescription", single);
+
+    const generic = try convertStructFieldType("const void *", allocator);
+    defer allocator.free(generic);
+    try std.testing.expectEqualStrings("[*c]const anyopaque", generic);
+}