py: Use a dummy type for referring to extern structs

Fixes msvc linker warnings about mismatching sizes between the mp_obj_fdfile_t
struct defined in file.c and the mp_uint_t declarations found in modsys.c and modbuiltins.c

3 files changed, 5 insertions, 5 deletions

diff --git a/py/modbuiltins.c b/py/modbuiltins.c
index 0985e25bf4..04141edec9 100644
--- a/py/modbuiltins.c
+++ b/py/modbuiltins.c
@@ -42,7 +42,7 @@
 #endif
 
 #if MICROPY_PY_IO
-extern mp_uint_t mp_sys_stdout_obj; // type is irrelevant, just need pointer
+extern struct _mp_dummy_t mp_sys_stdout_obj; // type is irrelevant, just need pointer
 #endif
 
 // args[0] is function from class body
diff --git a/py/modsys.c b/py/modsys.c
index 4ea60a697d..5051e72951 100644
--- a/py/modsys.c
+++ b/py/modsys.c
@@ -39,9 +39,9 @@
 /// \module sys - system specific functions
 
 // defined per port; type of these is irrelevant, just need pointer
-extern mp_uint_t mp_sys_stdin_obj;
-extern mp_uint_t mp_sys_stdout_obj;
-extern mp_uint_t mp_sys_stderr_obj;
+extern struct _mp_dummy_t mp_sys_stdin_obj;
+extern struct _mp_dummy_t mp_sys_stdout_obj;
+extern struct _mp_dummy_t mp_sys_stderr_obj;
 
 /// \constant version - Python language version that this implementation conforms to, as a string
 STATIC const MP_DEFINE_STR_OBJ(version_obj, "3.4.0");
diff --git a/py/obj.c b/py/obj.c
index c376adc03c..6c851dfb08 100644
--- a/py/obj.c
+++ b/py/obj.c
@@ -74,7 +74,7 @@ void mp_obj_print_helper(void (*print)(void *env, const char *fmt, ...), void *e
 void mp_obj_print(mp_obj_t o_in, mp_print_kind_t kind) {
 #if MICROPY_PY_IO
     // defined per port; type of these is irrelevant, just need pointer
-    extern mp_uint_t mp_sys_stdout_obj;
+    extern struct _mp_dummy_t mp_sys_stdout_obj;
     pfenv_t pfenv;
     pfenv.data = &mp_sys_stdout_obj;
     pfenv.print_strn = (void (*)(void *, const char *, mp_uint_t))mp_stream_write;