diff --git a/dlls/msvcrt/scanf.c b/dlls/msvcrt/scanf.c
index c51c5ab0967..89598970310 100644
--- a/dlls/msvcrt/scanf.c
+++ b/dlls/msvcrt/scanf.c
@@ -93,12 +93,12 @@ static int wchar2digit(MSVCRT_wchar_t c, int base) {
  */
 int CDECL MSVCRT_fscanf(MSVCRT_FILE *file, const char *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vfscanf(file, format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
 
@@ -107,12 +107,12 @@ int CDECL MSVCRT_fscanf(MSVCRT_FILE *file, const char *format, ...)
  */
 int CDECL MSVCRT_scanf(const char *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vfscanf(MSVCRT_stdin, format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
 
@@ -121,12 +121,12 @@ int CDECL MSVCRT_scanf(const char *format, ...)
  */
 int CDECL MSVCRT_fwscanf(MSVCRT_FILE *file, const MSVCRT_wchar_t *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vfwscanf(file, format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
 
@@ -136,12 +136,12 @@ int CDECL MSVCRT_fwscanf(MSVCRT_FILE *file, const MSVCRT_wchar_t *format, ...)
  */
 int CDECL MSVCRT_wscanf(const MSVCRT_wchar_t *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vfwscanf(MSVCRT_stdin, format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
 
@@ -151,12 +151,12 @@ int CDECL MSVCRT_wscanf(const MSVCRT_wchar_t *format, ...)
  */
 int CDECL MSVCRT_sscanf(const char *str, const char *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vsscanf(str, format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
 
@@ -166,12 +166,12 @@ int CDECL MSVCRT_sscanf(const char *str, const char *format, ...)
  */
 int CDECL MSVCRT_swscanf(const MSVCRT_wchar_t *str, const MSVCRT_wchar_t *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vswscanf(str, format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
 
@@ -181,11 +181,11 @@ int CDECL MSVCRT_swscanf(const MSVCRT_wchar_t *str, const MSVCRT_wchar_t *format
  */
 int CDECL _cscanf(const char *format, ...)
 {
-    va_list valist;
+    __ms_va_list valist;
     int res;
 
-    va_start(valist, format);
+    __ms_va_start(valist, format);
     res = MSVCRT_vcscanf(format, valist);
-    va_end(valist);
+    __ms_va_end(valist);
     return res;
 }
diff --git a/dlls/msvcrt/scanf.h b/dlls/msvcrt/scanf.h
index c236f48c4fd..fd1ad3b347d 100644
--- a/dlls/msvcrt/scanf.h
+++ b/dlls/msvcrt/scanf.h
@@ -48,7 +48,7 @@
 #ifdef CONSOLE
 #define _GETC_(file) (consumed++, _getch())
 #define _UNGETC_(nch, file) do { _ungetch(nch); consumed--; } while(0)
-#define _FUNCTION_ static int MSVCRT_vcscanf(const char *format, va_list ap)
+#define _FUNCTION_ static int MSVCRT_vcscanf(const char *format, __ms_va_list ap)
 #else
 #ifdef STRING
 #undef _EOF_
@@ -56,19 +56,19 @@
 #define _GETC_(file) (consumed++, *file++)
 #define _UNGETC_(nch, file) do { file--; consumed--; } while(0)
 #ifdef WIDE_SCANF
-#define _FUNCTION_ static int MSVCRT_vswscanf(const MSVCRT_wchar_t *file, const MSVCRT_wchar_t *format, va_list ap)
+#define _FUNCTION_ static int MSVCRT_vswscanf(const MSVCRT_wchar_t *file, const MSVCRT_wchar_t *format, __ms_va_list ap)
 #else /* WIDE_SCANF */
-#define _FUNCTION_ static int MSVCRT_vsscanf(const char *file, const char *format, va_list ap)
+#define _FUNCTION_ static int MSVCRT_vsscanf(const char *file, const char *format, __ms_va_list ap)
 #endif /* WIDE_SCANF */
 #else /* STRING */
 #ifdef WIDE_SCANF
 #define _GETC_(file) (consumed++, MSVCRT_fgetwc(file))
 #define _UNGETC_(nch, file) do { MSVCRT_ungetwc(nch, file); consumed--; } while(0)
-#define _FUNCTION_ static int MSVCRT_vfwscanf(MSVCRT_FILE* file, const MSVCRT_wchar_t *format, va_list ap)
+#define _FUNCTION_ static int MSVCRT_vfwscanf(MSVCRT_FILE* file, const MSVCRT_wchar_t *format, __ms_va_list ap)
 #else /* WIDE_SCANF */
 #define _GETC_(file) (consumed++, MSVCRT_fgetc(file))
 #define _UNGETC_(nch, file) do { MSVCRT_ungetc(nch, file); consumed--; } while(0)
-#define _FUNCTION_ static int MSVCRT_vfscanf(MSVCRT_FILE* file, const char *format, va_list ap)
+#define _FUNCTION_ static int MSVCRT_vfscanf(MSVCRT_FILE* file, const char *format, __ms_va_list ap)
 #endif /* WIDE_SCANF */
 #endif /* STRING */
 #endif /* CONSOLE */