Add Windows no_std project example (#63)

Author: johnthagen

.github/workflows/build.yml

@@ -30,7 +30,21 @@ jobs:
         with:
           toolchain: ${{ matrix.toolchain }}
       - name: Build
-        working-directory: no_std
+        working-directory: no_std/nix
+        run: cargo build --release --all-features
+  no_std_win:
+    name: no_std-win
+    strategy:
+      matrix:
+        toolchain: [ stable, nightly ]
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.toolchain }}
+      - name: Build
+        working-directory: no_std/win
         run: cargo build --release --all-features
   no_main_win:
     name: no_main-win

README.md

@@ -265,7 +265,7 @@ On macOS, the final stripped binary is reduced to 8KB.
 
 ![Minimum Rust: 1.30](https://img.shields.io/badge/Minimum%20Rust%20Version-1.30-brightgreen.svg)
 
-> Example project is located in the [`no_std`](no_std) folder.
+> Example projects are located in the [`no_std`](no_std) folder.
 
 Up until this point, our application was using the Rust standard library, `libstd`. `libstd`
 provides many convenient, well tested cross-platform APIs and data types. But if a user wants

no_std/.gitignore renamed to no_std/nix/.gitignore

@@ -0,0 +1 @@
+/target

no_std/Cargo.lock renamed to no_std/nix/Cargo.lock

@@ -0,0 +1,21 @@
+[package]
+name = "no_std_win"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+windows-sys = { version = "0.52.0", features = [
+    "Win32_Foundation",
+    "Win32_System_Threading", # for `ExitProcess`
+    "Win32_System_Console", # for `WriteConsoleA` etc.
+] }
+
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+opt-level = "z"     # Optimize for size.
+lto = true          # Enable Link Time Optimization
+codegen-units = 1   # Reduce number of codegen units to increase optimizations.
+panic = "abort"     # Abort on panic
+strip = true        # Automatically strip symbols from the binary.

no_std/Cargo.toml renamed to no_std/nix/Cargo.toml

@@ -0,0 +1,36 @@
+#![no_main]
+#![no_std]
+#![windows_subsystem = "console"]
+
+use core::ffi::c_void;
+use core::panic::PanicInfo;
+
+use windows_sys::Win32::System::Console::GetStdHandle;
+use windows_sys::Win32::System::Console::WriteConsoleA;
+use windows_sys::Win32::System::Console::STD_OUTPUT_HANDLE;
+use windows_sys::Win32::System::Threading::ExitProcess;
+
+#[panic_handler]
+fn panic(_: &PanicInfo<'_>) -> ! {
+    unsafe {
+        ExitProcess(1);
+    }
+}
+
+#[allow(non_snake_case)]
+#[no_mangle]
+fn mainCRTStartup() -> ! {
+    let message = "Hello, world!\n";
+    unsafe {
+        let console = GetStdHandle(STD_OUTPUT_HANDLE);
+        WriteConsoleA(
+            console,
+            message.as_ptr().cast::<c_void>(),
+            message.len() as u32,
+            core::ptr::null_mut(),
+            core::ptr::null(),
+        );
+
+        ExitProcess(0)
+    }
+}