Commit b31a03f134792b8fae20a625f68499c6548f8443 | zig

author	Ryan Liptak <squeek502@hotmail.com> 2025-11-08 01:39:15-08:00
committer	Ryan Liptak <squeek502@hotmail.com> 2025-11-08 17:11:12-08:00
log	b31a03f134792b8fae20a625f68499c6548f8443
tree	ad42b9f6811ab64efc449cb2fdcdb05868e3128b
parent	be4eaed7c41fb194014d862648ff586797e39e84

Let CRT take care of the entry point for wWinMain if libc is linked

Fixes #7852

Before, the modified test would fail with:

```
error: lld-link: undefined symbol: wWinMain
    note: referenced by C:\Users\Ryan\Programming\Zig\zig-x86_64-windows-0.15.1\lib\libc\mingw\crt\crtexewin.c:66
    note:               libmingw32.lib(ucrtexewin.obj):(wmain)
```

4 files changed, 90 insertions(+), 0 deletions(-)

lib
- std
  - start.zig
test
- standalone
  - windows_entry_points
    build.zig
    main.zig
    wwinmain.zig

lib/std/start.zig+8

 @@ -61,6 +61,10 @@ comptime {
                 } else if (!@typeInfo(@TypeOf(root.main)).@"fn".calling_convention.eql(.c)) {
                     @export(&main, .{ .name = "main" });
                 }
+            } else if (native_os == .windows and builtin.link_libc and @hasDecl(root, "wWinMain")) {
+                if (!@typeInfo(@TypeOf(root.wWinMain)).@"fn".calling_convention.eql(.c)) {
+                    @export(&wWinMain, .{ .name = "wWinMain" });
+                }
             } else if (native_os == .windows) {
                 if (!@hasDecl(root, "WinMain") and !@hasDecl(root, "WinMainCRTStartup") and
                     !@hasDecl(root, "wWinMain") and !@hasDecl(root, "wWinMainCRTStartup"))
 @@ -527,6 +531,10 @@ fn wWinMainCRTStartup() callconv(.withStackAlign(.c, 1)) noreturn {
     std.os.windows.ntdll.RtlExitUserProcess(@as(std.os.windows.UINT, @bitCast(result)));
 }
+fn wWinMain(hInstance: *anyopaque, hPrevInstance: ?*anyopaque, pCmdLine: [*:0]u16, nCmdShow: c_int) callconv(.c) c_int {
+    return root.wWinMain(@ptrCast(hInstance), @ptrCast(hPrevInstance), pCmdLine, @intCast(nCmdShow));
+}
 fn posixCallMainAndExit(argc_argv_ptr: [*]usize) callconv(.c) noreturn {
     // We're not ready to panic until thread local storage is initialized.
     @setRuntimeSafety(false);

test/standalone/windows_entry_points/build.zig+62

...	@@ -77,4 +77,66 @@ pub fn build(b: *std.Build) void {	...	@@ -77,4 +77,66 @@ pub fn build(b: *std.Build) void {
77	_ = exe.getEmittedBin();	77	_ = exe.getEmittedBin();
78	test_step.dependOn(&exe.step);	78	test_step.dependOn(&exe.step);
79	}	79	}
		80
		81	{
		82	const exe = b.addExecutable(.{
		83	.name = "zig_main",
		84	.root_module = b.createModule(.{
		85	.root_source_file = b.path("main.zig"),
		86	.target = target,
		87	.optimize = .Debug,
		88	}),
		89	});
		90
		91	_ = exe.getEmittedBin();
		92	test_step.dependOn(&exe.step);
		93	}
		94
		95	{
		96	const exe = b.addExecutable(.{
		97	.name = "zig_main_link_libc",
		98	.root_module = b.createModule(.{
		99	.root_source_file = b.path("main.zig"),
		100	.target = target,
		101	.optimize = .Debug,
		102	.link_libc = true,
		103	}),
		104	});
		105
		106	_ = exe.getEmittedBin();
		107	test_step.dependOn(&exe.step);
		108	}
		109
		110	{
		111	const exe = b.addExecutable(.{
		112	.name = "zig_wwinmain",
		113	.root_module = b.createModule(.{
		114	.root_source_file = b.path("wwinmain.zig"),
		115	.target = target,
		116	.optimize = .Debug,
		117	}),
		118	});
		119	exe.mingw_unicode_entry_point = true;
		120	// Note: `exe.subsystem = .windows;` is not necessary
		121
		122	_ = exe.getEmittedBin();
		123	test_step.dependOn(&exe.step);
		124	}
		125
		126	{
		127	const exe = b.addExecutable(.{
		128	.name = "zig_wwinmain_link_libc",
		129	.root_module = b.createModule(.{
		130	.root_source_file = b.path("wwinmain.zig"),
		131	.target = target,
		132	.optimize = .Debug,
		133	.link_libc = true,
		134	}),
		135	});
		136	exe.mingw_unicode_entry_point = true;
		137	// Note: `exe.subsystem = .windows;` is not necessary
		138
		139	_ = exe.getEmittedBin();
		140	test_step.dependOn(&exe.step);
		141	}
80	}	142	}

test/standalone/windows_entry_points/main.zig created+5

...	@@ -0,0 +1,5 @@
1	const std = @import("std");
2
3	pub fn main() void {
4	std.debug.print("hello from Zig main\n", .{});
5	}

test/standalone/windows_entry_points/wwinmain.zig created+15

...	@@ -0,0 +1,15 @@
1	const std = @import("std");
2
3	pub fn wWinMain(
4	inst: std.os.windows.HINSTANCE,
5	prev: ?std.os.windows.HINSTANCE,
6	cmd_line: std.os.windows.LPWSTR,
7	cmd_show: c_int,
8	) std.os.windows.INT {
9	_ = inst;
10	_ = prev;
11	_ = cmd_line;
12	_ = cmd_show;
13	std.debug.print("hello from Zig wWinMain\n", .{});
14	return 0;
15	}