Deduce whehter to export nif_init

Author: filmor

rustler/Cargo.toml

@@ -19,7 +19,6 @@ nif_version_2_15 = ["nif_version_2_14"]
 nif_version_2_16 = ["nif_version_2_15"]
 nif_version_2_17 = ["nif_version_2_16"]
 serde = ["dep:serde"]
-staticlib = ["rustler_codegen/staticlib"]
 
 [dependencies]
 inventory = "0.3"

rustler_codegen/Cargo.toml

@@ -12,9 +12,6 @@ edition = "2021"
 name = "rustler_codegen"
 proc-macro = true
 
-[features]
-staticlib = []
-
 [dependencies]
 syn = { version = "2.0", features = ["full", "extra-traits"] }
 quote = "1.0"

rustler_codegen/src/init.rs

@@ -136,15 +136,34 @@ impl From<InitMacroInput> for proc_macro2::TokenStream {
             }
         };
 
-        let nif_init_name = if cfg!(feature = "staticlib") {
+        let nif_init_name = {
             let lib_name = std::env::var("CARGO_CRATE_NAME").unwrap();
             format!("{lib_name}_nif_init")
-        } else {
-            "nif_init".to_string()
         };
 
         let nif_init_name = Ident::new(&nif_init_name, Span::call_site());
 
+        let should_generate_primary_nif = std::env::var("RUSTLER_PRIMARY_NIF_INIT").is_ok()
+            || std::env::var("CARGO_PRIMARY_PACKAGE").is_ok();
+
+        let maybe_primary_nif_init = if should_generate_primary_nif {
+            quote! {
+                #[cfg(not(windows))]
+                #[no_mangle]
+                fn nif_init() -> *const ::rustler::codegen_runtime::DEF_NIF_ENTRY {
+                    #nif_init_name()
+                }
+
+                #[cfg(windows)]
+                #[no_mangle]
+                fn nif_init(callbacks: *mut ::rustler::codegen_runtime::DynNifCallbacks) -> *const ::rustler::codegen_runtime::DEF_NIF_ENTRY {
+                    #nif_init_name(callbacks)
+                }
+            }
+        } else {
+            quote!()
+        };
+
         quote! {
             #maybe_warning
 
@@ -167,6 +186,8 @@ impl From<InitMacroInput> for proc_macro2::TokenStream {
 
                 #inner
             }
+
+            #maybe_primary_nif_init
         }
     }
 }