Implement "static" feature flag for FTD2XX static linking.

.github/workflows/ci.yml

@@ -85,7 +85,7 @@ jobs:
         with:
           toolchain: stable
           target: ${{ matrix.target }}
-      - run: cargo test --target ${{ matrix.target }}
+      - run: cargo test --features=static --target ${{ matrix.target }}
 
   windows_test:
     name: Windows Unit Tests

Cargo.toml

@@ -28,5 +28,8 @@ bindgen = { version = "~0.57.0", optional = true }
 [dev-dependencies]
 version-sync = "~0.9.1"
 
+[features]
+static = []
+
 [badges]
 maintenance = { status = "passively-maintained" }

README.md

@@ -14,12 +14,14 @@ the unsafe C bindings.
 ## Usage
 Simply add this crate as a dependency in your `Cargo.toml`.
 The static library is distributed in this crate with permission from FTDI.
+The default feature set will use dynamic linking.
 
 ```toml
 [dependencies]
 libftd2xx-ffi = "~0.6.0"
 ```
 
+### Bindgen
 The default feature set will use pre-generated bindings.
 This is only available for Windows x86_64 and Linux x86_64 platforms.
 
@@ -33,28 +35,49 @@ libftd2xx-ffi = { version = "~0.6.0", features = ["bindgen"] }
 Bindgen has additional dependencies that must be installed in order to
 compile successfully, see the [bindgen requirements] page for more details.
 
+### Static Linking
+Static linking the FTD2XX library into this crate can be done by using
+the ["static"] feature flag.
+```toml
+[dependencies]
+libftd2xx-ffi = { version = "~0.6.0", features = ["static"] }
+```
+For GNU/Linux users, no further work is needed. Technically this may be preferred.
+However there may be license incompatibilities (static linking with GPL code).
+If in doubt, check the FTDI driver license terms.
+
+On Windows, we rely on MSVC and a manually set the "LIBMSVC_PATH" environment variable.
+For example a possible 2019 Community installation path may be:
+```
+C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29333\lib\
+```
+This brings in legacy_stdio_definitions.lib and user32.lib. It seems to play nicely with rust,
+but you may end up with multiple defined symbol errors if using this crate as a c/c++ dependency.
+
 ## Supported Targets
 
 ### Tested Targets
 
-* `x86_64-pc-windows-msvc` (dynamic linking only)
-* `x86_64-unknown-linux-gnu` (static linking only)
-* `x86_64-unknown-linux-musl` (static linking only)
+* `i686-pc-windows-msvc` (dynamic + static)
+* `i686-unknown-linux-gnu` (dynamic + static)
+* `i686-unknown-linux-musl` (static)
+* `x86_64-pc-windows-msvc` (dynamic + static)
+* `x86_64-unknown-linux-gnu` (dynamic + static)
+* `x86_64-unknown-linux-musl` (static)
 
 ### Untested Targets
 
 These targets are provided, but they are untested.
 Use at your own risk.
 
-* `aarch64-unknown-linux-gnu` (static linking only)
-* `aarch64-unknown-linux-musl` (static linking only)
-* `arm-unknown-linux-gnueabihf` (static linking only)
-* `arm-unknown-linux-musleabihf` (static linking only)
-* `armv7-unknown-linux-gnueabihf` (static linking only)
-* `armv7-unknown-linux-musleabihf` (static linking only)
-* `i686-pc-windows-msvc` (dynamic linking only)
-* `i686-unknown-linux-gnu` (static linking only)
-* `i686-unknown-linux-musl` (static linking only)
+* `aarch64-unknown-linux-gnu` (dynamic + static)
+* `aarch64-unknown-linux-musl` (dynamic + static)
+* `arm-unknown-linux-gnueabihf` (dynamic + static)
+* `arm-unknown-linux-musleabihf` (dynamic + static)
+* `armv7-unknown-linux-gnueabihf` (dynamic + static)
+* `armv7-unknown-linux-musleabihf` (dynamic + static)
+* `i686-unknown-linux-musl` (dynamic)
+* `x86_64-unknown-linux-musl` (dynamic)
 
 ## References
 

build.rs

@@ -3,8 +3,26 @@ use std::env;
 fn search_path<'a>() -> &'a str {
     match env::var("CARGO_CFG_TARGET_OS").unwrap().as_str() {
         "windows" => match env::var("CARGO_CFG_TARGET_ARCH").unwrap().as_str() {
-            "x86_64" => "vendor/windows/amd64",
-            "x86" => "vendor/windows/i386",
+            "x86_64" => {
+                #[cfg(not(feature = "static"))]
+                {
+                    "vendor\\windows\\amd64"
+                }
+                #[cfg(feature = "static")]
+                {
+                    "vendor\\windows\\Static\\amd64"
+                }
+            }
+            "x86" => {
+                #[cfg(not(feature = "static"))]
+                {
+                    "vendor\\windows\\i386"
+                }
+                #[cfg(feature = "static")]
+                {
+                    "vendor\\windows\\Static\\i386"
+                }
+            }
             target_arch => panic!("Target architecture not supported: {}", target_arch),
         },
         "linux" => match env::var("CARGO_CFG_TARGET_ARCH").unwrap().as_str() {
@@ -66,6 +84,36 @@ fn clang_args() -> &'static [&'static str] {
     }
 }
 
+#[cfg(not(feature = "static"))]
+fn linker_options() {
+    println!("cargo:rustc-link-lib=dylib=ftd2xx");
+}
+
+#[cfg(feature = "static")]
+fn linker_options() {
+    println!("cargo:rustc-link-lib=static=ftd2xx");
+
+    match env::var("CARGO_CFG_TARGET_OS").unwrap().as_str() {
+        "windows" => {
+            let libmsvc_path = if let Some(libmsvc_path) = env::var_os("LIBMSVC_PATH") {
+                match env::var("CARGO_CFG_TARGET_ARCH").unwrap().as_str() {
+                    "x86_64" => format!("{}{}", libmsvc_path.into_string().unwrap(), "\\x64"),
+                    "x86" => format!("{}{}", libmsvc_path.into_string().unwrap(), "\\x64"),
+                    target_arch => panic!("Target architecture not supported: {}", target_arch),
+                }
+            } else {
+                panic!("LIBMSVC_PATH environment variable not found.");
+            };
+
+            println!("cargo:rustc-link-search=native={}", libmsvc_path);
+            println!("cargo:rustc-link-lib=static=legacy_stdio_definitions");
+            println!("cargo:rustc-link-lib=user32");
+        }
+        "linux" => {}
+        target_os => panic!("Target OS not supported: {}", target_os),
+    }
+}
+
 fn main() {
     let cwd = env::current_dir().unwrap();
     let mut header = cwd.clone();
@@ -77,8 +125,10 @@ fn main() {
         "cargo:rustc-link-search=native={}",
         search.to_str().unwrap()
     );
-    println!("cargo:rustc-link-lib=static=ftd2xx");
+    linker_options();
+
     println!("cargo:rerun-if-changed={}", header.to_str().unwrap());
+    println!("cargo:rerun-if-env-changed=LIBMSVC_PATH");
 
     #[cfg(feature = "bindgen")]
     {

tests/lib.rs

@@ -1,8 +1,8 @@
-use libftd2xx_ffi::FT_GetLibraryVersion;
-
 #[test]
 #[cfg(not(windows))]
 fn version() {
+    use libftd2xx_ffi::FT_GetLibraryVersion;
+
     let mut dw_library_ver = 0;
 
     let ft_status = unsafe { FT_GetLibraryVersion(&mut dw_library_ver) };