From 6d12f57d1441a32a3aa13c94f4fde509c5b35c07 Mon Sep 17 00:00:00 2001
From: Shib <contact@shib.cc>
Date: Wed, 13 Apr 2022 12:01:55 +0200
Subject: [PATCH] Add (gen > c) -> Added callconv attribute for function

---
 vlib/v/gen/c/fn.v  |  5 +++++
 vlib/v/parser/fn.v | 13 +++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/vlib/v/gen/c/fn.v b/vlib/v/gen/c/fn.v
index e55383c288..520267b213 100644
--- a/vlib/v/gen/c/fn.v
+++ b/vlib/v/gen/c/fn.v
@@ -2153,6 +2153,11 @@ fn (mut g Gen) write_fn_attrs(attrs []ast.Attr) string {
 			'_fastcall' {
 				fn_attrs += '__fastcall '
 			}
+			"callconv" {
+				if attr.has_arg {
+					fn_attrs += '__$attr.arg '
+				}
+			}
 			'console' {
 				g.force_main_console = true
 			}
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index e956f2e116..d00fe81195 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -197,6 +197,19 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 			'c2v_variadic' { is_c2v_variadic = true }
 			'use_new' { is_ctor_new = true }
 			'markused' { is_markused = true }
+			"windows_stdcall" {
+				p.warn_with_pos('windows_stdcall has been deprecated, it will be an error soon', p.tok.pos())
+			}
+			"_fastcall" {
+				p.warn_with_pos('_fastcall has been deprecated, it will be an error soon', p.tok.pos())
+			}
+			"callconv" {
+				if fna.has_arg {
+					if fna.arg !in ['stdcall', 'fastcall', 'cdecl'] {
+						p.error_with_pos('unsupported calling convention, supported are stdcall, fastcall and cdecl', p.tok.pos())
+					 }
+				}
+			}
 			else {}
 		}
 	}