diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index d940241ccd..85c26ac2ec 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -96,6 +96,7 @@ mut:
 	is_json_fn                bool // inside json.encode()
 	is_js_call                bool // for handling a special type arg #1 `json.decode(User, ...)`
 	is_fn_index_call          bool
+	is_cc_msvc                bool   // g.pref.ccompiler == 'msvc'
 	vlines_path               string // set to the proper path for generating #line directives
 	optionals                 map[string]string // to avoid duplicates
 	done_optionals            shared []string   // to avoid duplicates
@@ -258,6 +259,7 @@ pub fn gen(files []&ast.File, table &ast.Table, pref &pref.Preferences) string {
 		inner_loop: &ast.EmptyStmt{}
 		field_data_type: ast.Type(table.find_type_idx('FieldData'))
 		init: strings.new_builder(100)
+		is_cc_msvc: pref.ccompiler == 'msvc'
 	}
 	// anon fn may include assert and thus this needs
 	// to be included before any test contents are written
@@ -557,6 +559,7 @@ fn cgen_process_one_file_cb(p &pool.PoolProcessor, idx int, wid int) &Gen {
 		done_optionals: global_g.done_optionals
 		is_autofree: global_g.pref.autofree
 		referenced_fns: global_g.referenced_fns
+		is_cc_msvc: global_g.is_cc_msvc
 	}
 	g.gen_file()
 	return g
@@ -1346,11 +1349,10 @@ pub fn (mut g Gen) write_fn_typesymbol_declaration(sym ast.TypeSymbol) {
 
 		mut call_conv := ''
 		mut msvc_call_conv := ''
-		is_cc_msvc := g.pref.ccompiler == 'msvc'
 		for attr in func.attrs {
 			match attr.name {
 				'callconv' {
-					if is_cc_msvc {
+					if g.is_cc_msvc {
 						msvc_call_conv = '__$attr.arg '
 					} else {
 						call_conv = '$attr.arg'
diff --git a/vlib/v/gen/c/fn.v b/vlib/v/gen/c/fn.v
index 02fcfa34a5..4f67dd8ce1 100644
--- a/vlib/v/gen/c/fn.v
+++ b/vlib/v/gen/c/fn.v
@@ -2148,13 +2148,13 @@ fn (mut g Gen) write_fn_attrs(attrs []ast.Attr) string {
 			'windows_stdcall' {
 				// windows attributes (msvc/mingw)
 				// prefixed by windows to indicate they're for advanced users only and not really supported by V.
-				fn_attrs += '__stdcall '
+				fn_attrs += call_convention_attribute('stdcall', g.is_cc_msvc)
 			}
 			'_fastcall' {
-				fn_attrs += '__fastcall '
+				fn_attrs += call_convention_attribute('fastcall', g.is_cc_msvc)
 			}
 			'callconv' {
-				fn_attrs += '__$attr.arg '
+				fn_attrs += call_convention_attribute(attr.arg, g.is_cc_msvc)
 			}
 			'console' {
 				g.force_main_console = true
@@ -2166,3 +2166,7 @@ fn (mut g Gen) write_fn_attrs(attrs []ast.Attr) string {
 	}
 	return fn_attrs
 }
+
+fn call_convention_attribute(cconvention string, is_cc_msvc bool) string {
+	return if is_cc_msvc { '__$cconvention ' } else { '__attribute__(($cconvention)) ' }
+}