Issue #2443: Added a new macro, Py_VA_COPY, which is equivalent to C99

va_copy, but available on all python platforms.  Untabified a few
unrelated files.

Include/pyport.h

@@ -822,4 +822,14 @@ extern pid_t forkpty(int *, char *, struct termios *, struct winsize *);
 #define Py_ULL(x) Py_LL(x##U)
 #endif
 
+#ifdef VA_LIST_IS_ARRAY
+#define Py_VA_COPY(x, y) Py_MEMCPY((x), (y), sizeof(va_list))
+#else
+#ifdef __va_copy
+#define Py_VA_COPY __va_copy
+#else
+#define Py_VA_COPY(x, y) (x) = (y)
+#endif
+#endif
+
 #endif /* Py_PYPORT_H */

Misc/NEWS

@@ -583,6 +583,10 @@ Core and Builtins
 C-API
 -----
 
+- Issue #2443: A new macro, `Py_VA_COPY`, copies the state of the
+  variable argument list.  `Py_VA_COPY` is equivalent to C99
+  `va_copy`, but available on all python platforms.
+
 - PySlice_GetIndicesEx now clips the step to [-PY_SSIZE_T_MAX, PY_SSIZE_T_MAX]
   instead of [-PY_SSIZE_T_MAX-1, PY_SSIZE_T_MAX].  This makes it safe to do
   "step = -step" when reversing a slice.

Objects/abstract.c

@@ -2311,15 +2311,7 @@ objargs_mktuple(va_list va)
     va_list countva;
     PyObject *result, *tmp;
 
-#ifdef VA_LIST_IS_ARRAY
+        Py_VA_COPY(countva, va);
-    memcpy(countva, va, sizeof(va_list));
-#else
-#ifdef __va_copy
-    __va_copy(countva, va);
-#else
-    countva = va;
-#endif
-#endif
 
     while (((PyObject *)va_arg(countva, PyObject *)) != NULL)
         ++n;

Objects/bytesobject.c

@@ -173,15 +173,7 @@ PyBytes_FromFormatV(const char *format, va_list vargs)
     char *s;
     PyObject* string;
 
-#ifdef VA_LIST_IS_ARRAY
+    Py_VA_COPY(count, vargs);
-    Py_MEMCPY(count, vargs, sizeof(va_list));
-#else
-#ifdef  __va_copy
-    __va_copy(count, vargs);
-#else
-    count = vargs;
-#endif
-#endif
     /* step 1: figure out how large a buffer we need */
     for (f = format; *f; f++) {
         if (*f == '%') {

Objects/unicodeobject.c

@@ -755,15 +755,7 @@ PyUnicode_FromFormatV(const char *format, va_list vargs)
     char fmt[61]; /* should be enough for %0width.precisionlld */
     const char *copy;
 
-#ifdef VA_LIST_IS_ARRAY
+    Py_VA_COPY(count, vargs); 
-    Py_MEMCPY(count, vargs, sizeof(va_list));
-#else
-#ifdef  __va_copy
-    __va_copy(count, vargs);
-#else
-    count = vargs;
-#endif
-#endif
     /* step 1: count the number of %S/%R/%A/%s format specifications
      * (we call PyObject_Str()/PyObject_Repr()/PyObject_ASCII()/
      * PyUnicode_DecodeUTF8() for these objects once during step 3 and put the

Python/getargs.c

@@ -105,15 +105,7 @@ PyArg_VaParse(PyObject *args, const char *format, va_list va)
 {
     va_list lva;
 
-#ifdef VA_LIST_IS_ARRAY
+        Py_VA_COPY(lva, va);
-    memcpy(lva, va, sizeof(va_list));
-#else
-#ifdef __va_copy
-    __va_copy(lva, va);
-#else
-    lva = va;
-#endif
-#endif
 
     return vgetargs1(args, format, &lva, 0);
 }
@@ -123,15 +115,7 @@ _PyArg_VaParse_SizeT(PyObject *args, char *format, va_list va)
 {
     va_list lva;
 
-#ifdef VA_LIST_IS_ARRAY
+        Py_VA_COPY(lva, va);
-    memcpy(lva, va, sizeof(va_list));
-#else
-#ifdef __va_copy
-    __va_copy(lva, va);
-#else
-    lva = va;
-#endif
-#endif
 
     return vgetargs1(args, format, &lva, FLAG_SIZE_T);
 }
@@ -1376,15 +1360,7 @@ PyArg_VaParseTupleAndKeywords(PyObject *args,
         return 0;
     }
 
-#ifdef VA_LIST_IS_ARRAY
+        Py_VA_COPY(lva, va);
-    memcpy(lva, va, sizeof(va_list));
-#else
-#ifdef __va_copy
-    __va_copy(lva, va);
-#else
-    lva = va;
-#endif
-#endif
 
     retval = vgetargskeywords(args, keywords, format, kwlist, &lva, 0);
     return retval;
@@ -1408,15 +1384,7 @@ _PyArg_VaParseTupleAndKeywords_SizeT(PyObject *args,
         return 0;
     }
 
-#ifdef VA_LIST_IS_ARRAY
+        Py_VA_COPY(lva, va);
-    memcpy(lva, va, sizeof(va_list));
-#else
-#ifdef __va_copy
-    __va_copy(lva, va);
-#else
-    lva = va;
-#endif
-#endif
 
     retval = vgetargskeywords(args, keywords, format,
                               kwlist, &lva, FLAG_SIZE_T);

Python/modsupport.c

@@ -456,15 +456,7 @@ va_build_value(const char *format, va_list va, int flags)
     int n = countformat(f, '\0');
     va_list lva;
 
-#ifdef VA_LIST_IS_ARRAY
+        Py_VA_COPY(lva, va);
-    memcpy(lva, va, sizeof(va_list));
-#else
-#ifdef __va_copy
-    __va_copy(lva, va);
-#else
-    lva = va;
-#endif
-#endif
 
     if (n < 0)
         return NULL;