Fix Windows API functions

CHANGELOG.md

@@ -20,6 +20,8 @@ versions.
 
 - The optional `register` attribute on `#[register_impl]` works as advertised
   now (#638)
+- API functions for Windows are correctly assigned now for NIF version 2.15 and
+  above (#635)
 
 ### Changed
 

rustler/src/dynamic.rs

@@ -45,7 +45,7 @@ impl From<ErlNifTermType> for TermType {
 }
 
 pub fn get_type(term: Term) -> TermType {
-    if cfg!(feature = "nif_version_2_15") && !cfg!(target_family = "windows") {
+    if cfg!(feature = "nif_version_2_15") {
         term.get_erl_type().into()
     } else if term.is_atom() {
         TermType::Atom

rustler_sys/build.rs

@@ -139,7 +139,7 @@ impl<'a> ApiBuilder for WinForwardersApiBuilder<'a> {
         )
         .unwrap();
         writeln!(self.0, "#[inline]").unwrap();
-        writeln!(self.0, "pub unsafe fn {}({})", name, args).unwrap();
+        writeln!(self.0, "pub unsafe extern \"C\" fn {}({})", name, args).unwrap();
         write_ret(self.0, ret);
         writeln!(self.0, "{{").unwrap();
         writeln!(
@@ -845,18 +845,18 @@ fn build_api(b: &mut dyn ApiBuilder, opts: &GenerateOptions) {
 
     // 2.15 was introduced in OTP 22
     if opts.nif_version >= (2, 15) {
+        b.dummy("enif_select_x");
         b.func(
-            "ErlNifTermType",
-            "enif_term_type",
-            "env: *mut ErlNifEnv, term: ERL_NIF_TERM",
+            "ERL_NIF_TERM",
+            "enif_make_monitor_term",
+            "env: *mut ErlNifEnv, mon: *const ErlNifMonitor",
         );
-
         b.func("c_int", "enif_is_pid_undefined", "pid: *const ErlNifPid");
         b.func("", "enif_set_pid_undefined", "pid: *mut ErlNifPid");
         b.func(
-            "ERL_NIF_TERM",
-            "enif_make_monitor_term",
-            "env: *mut ErlNifEnv, mon: *const ErlNifMonitor",
+            "ErlNifTermType",
+            "enif_term_type",
+            "env: *mut ErlNifEnv, term: ERL_NIF_TERM",
         );
     }
 
@@ -868,15 +868,21 @@ fn build_api(b: &mut dyn ApiBuilder, opts: &GenerateOptions) {
 
     // 2.17 was introduced in OTP 26
     if opts.nif_version >= (2, 17) {
+        b.func("c_int", "enif_get_string_length", "env: *mut ErlNifEnv, list: ERL_NIF_TERM, len: *mut c_uint, encoding: ErlNifCharEncoding");
+        b.func("c_int", "enif_make_new_atom", "env: *mut ErlNifEnv, name: *const c_char, atom: *mut ERL_NIF_TERM, encoding: ErlNifCharEncoding");
+        b.func("c_int", "enif_make_new_atom_len", "env: *mut ErlNifEnv, name: *const c_char, len: size_t, atom: *mut ERL_NIF_TERM, encoding: ErlNifCharEncoding");
         b.func(
             "c_int",
             "enif_set_option",
             "env: *mut ErlNifEnv, opt: ErlNifOption",
         );
-        b.func("c_int", "enif_get_string_length", "env: *mut ErlNifEnv, list: ERL_NIF_TERM, len: *mut c_uint, encoding: ErlNifCharEncoding");
-        b.func("c_int", "enif_make_new_atom", "env: *mut ErlNifEnv, name: *const c_char, atom: *mut ERL_NIF_TERM, encoding: ErlNifCharEncoding");
-        b.func("c_int", "enif_make_new_atom_len", "env: *mut ErlNifEnv, name: *const c_char, len: size_t, atom: *mut ERL_NIF_TERM, encoding: ErlNifCharEncoding");
     }
+
+    // If new functions are added for a new OTP version, ensure that *all* functions are added in
+    // the *correct order*. Failure to do so will result in errors on Windows, as the callback
+    // handling uses the `TWinDynNifCallbacks` struct.
+    //
+    // The correct order can (currently) by derived from the `erl_nif_api_funcs.h` header.
 }
 
 fn get_nif_version_from_features() -> (u32, u32) {