From a450016eb1816a8f0989626dde4b0c1865cba33d Mon Sep 17 00:00:00 2001
From: Ryan Liptak <squeek502@hotmail.com>
Date: Fri, 1 May 2026 19:24:59 -0700
Subject: [PATCH] Add tests for DllMain to windows_entry_points standalone test

---
 .../standalone/windows_entry_points/build.zig | 71 +++++++++++++++++++
 .../standalone/windows_entry_points/dllmain.c |  9 +++
 .../windows_entry_points/dllmain.zig          | 18 +++++
 .../windows_entry_points/loaddll.zig          | 13 ++++
 4 files changed, 111 insertions(+)
 create mode 100644 test/standalone/windows_entry_points/dllmain.c
 create mode 100644 test/standalone/windows_entry_points/dllmain.zig
 create mode 100644 test/standalone/windows_entry_points/loaddll.zig

diff --git a/test/standalone/windows_entry_points/build.zig b/test/standalone/windows_entry_points/build.zig
index 236ebe95c632112c9cefc8afd912c247d103dc52..d63de59c2b970b7bfe04bcd95578eaae9fc6b88d 100644
--- a/test/standalone/windows_entry_points/build.zig
+++ b/test/standalone/windows_entry_points/build.zig
@@ -139,4 +139,75 @@ pub fn build(b: *std.Build) void {
         _ = exe.getEmittedBin();
         test_step.dependOn(&exe.step);
     }
+
+    const load_dll_exe = b.addExecutable(.{ .name = "load_dll", .root_module = b.createModule(.{
+        .root_source_file = b.path("loaddll.zig"),
+        .target = target,
+        .optimize = .Debug,
+    }) });
+
+    {
+        const dll = b.addLibrary(.{
+            .name = "zig_dllmain",
+            .linkage = .dynamic,
+            .root_module = b.createModule(.{
+                .root_source_file = b.path("dllmain.zig"),
+                .target = target,
+                .optimize = .Debug,
+            }),
+        });
+
+        const run = b.addRunArtifact(load_dll_exe);
+        run.addArtifactArg(dll);
+        run.expectStdErrEqual("hello from DllMain");
+        run.expectStdOutEqual("");
+        run.expectExitCode(0);
+        run.skip_foreign_checks = true;
+
+        test_step.dependOn(&run.step);
+    }
+
+    {
+        const dll = b.addLibrary(.{
+            .name = "zig_dllmain_link_libc",
+            .linkage = .dynamic,
+            .root_module = b.createModule(.{
+                .root_source_file = b.path("dllmain.zig"),
+                .target = target,
+                .optimize = .Debug,
+                .link_libc = true,
+            }),
+        });
+
+        const run = b.addRunArtifact(load_dll_exe);
+        run.addArtifactArg(dll);
+        run.expectStdErrEqual("hello from DllMain");
+        run.expectStdOutEqual("");
+        run.expectExitCode(0);
+        run.skip_foreign_checks = true;
+
+        test_step.dependOn(&run.step);
+    }
+
+    {
+        const dll = b.addLibrary(.{
+            .name = "c_dllmain",
+            .linkage = .dynamic,
+            .root_module = b.createModule(.{
+                .target = target,
+                .optimize = .Debug,
+                .link_libc = true,
+            }),
+        });
+        dll.root_module.addCSourceFile(.{ .file = b.path("dllmain.c") });
+
+        const run = b.addRunArtifact(load_dll_exe);
+        run.addArtifactArg(dll);
+        run.expectStdErrEqual("hello from DllMain");
+        run.expectStdOutEqual("");
+        run.expectExitCode(0);
+        run.skip_foreign_checks = true;
+
+        test_step.dependOn(&run.step);
+    }
 }
diff --git a/test/standalone/windows_entry_points/dllmain.c b/test/standalone/windows_entry_points/dllmain.c
new file mode 100644
index 0000000000000000000000000000000000000000..266ce5876bd2da206f8cf1c0fe6e72d8bd6635d3
--- /dev/null
+++ b/test/standalone/windows_entry_points/dllmain.c
@@ -0,0 +1,9 @@
+#include <windows.h>
+#include <stdio.h>
+
+BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) {
+    if (fdwReason == DLL_PROCESS_ATTACH) {
+        fprintf(stderr, "hello from DllMain");
+    }
+    return TRUE;
+}
diff --git a/test/standalone/windows_entry_points/dllmain.zig b/test/standalone/windows_entry_points/dllmain.zig
new file mode 100644
index 0000000000000000000000000000000000000000..f4df3a5afbad2fc17693a963650fc88f63a027c3
--- /dev/null
+++ b/test/standalone/windows_entry_points/dllmain.zig
@@ -0,0 +1,18 @@
+const std = @import("std");
+const windows = std.os.windows;
+
+const DLL_PROCESS_ATTACH = 1;
+
+pub fn DllMain(
+    hinstDLL: windows.HINSTANCE,
+    fdwReason: windows.DWORD,
+    lpReserved: windows.LPVOID,
+) windows.BOOL {
+    _ = hinstDLL;
+    _ = lpReserved;
+    switch (fdwReason) {
+        DLL_PROCESS_ATTACH => std.debug.print("hello from DllMain", .{}),
+        else => {},
+    }
+    return .TRUE;
+}
diff --git a/test/standalone/windows_entry_points/loaddll.zig b/test/standalone/windows_entry_points/loaddll.zig
new file mode 100644
index 0000000000000000000000000000000000000000..116fe36a645bf34fa199f2f8c50701ddbd3152b7
--- /dev/null
+++ b/test/standalone/windows_entry_points/loaddll.zig
@@ -0,0 +1,13 @@
+const std = @import("std");
+const windows = std.os.windows;
+
+extern "kernel32" fn LoadLibraryW(windows.LPCWSTR) callconv(.winapi) ?windows.HMODULE;
+
+pub fn main(init: std.process.Init) !void {
+    const arena = init.arena.allocator();
+    const args = try init.minimal.args.toSlice(arena);
+    if (args.len < 2) return error.NoDllPathSpecified;
+    const dll_path = args[1];
+    const dll_path_w = try std.unicode.wtf8ToWtf16LeAllocZ(arena, dll_path);
+    _ = LoadLibraryW(dll_path_w) orelse return error.FailedToLoadDll;
+}
-- 
2.54.0