kernel32: GMEM_FIXED blocks cannot be 0 size.

dlls/kernel32/heap.c

@@ -362,7 +362,7 @@ HGLOBAL WINAPI GlobalAlloc(
 
    if((flags & GMEM_MOVEABLE)==0) /* POINTER */
    {
-      palloc=HeapAlloc(GetProcessHeap(), hpflags, size);
+      palloc = HeapAlloc( GetProcessHeap(), hpflags, max( 1, size ));
       TRACE( "(flags=%04x) returning %p\n",  flags, palloc );
       return palloc;
    }
@@ -961,10 +961,16 @@ SIZE_T WINAPI GlobalCompact( DWORD minfree )
  *  Windows memory management does not provide a separate local heap
  *  and global heap.
  */
-HLOCAL WINAPI LocalAlloc(
-                UINT flags, /* [in] Allocation attributes */
-                SIZE_T size /* [in] Number of bytes to allocate */
-) {
+HLOCAL WINAPI LocalAlloc( UINT flags, SIZE_T size )
+{
+    /* LocalAlloc allows a 0-size fixed block, but GlobalAlloc doesn't */
+    if (!(flags & LMEM_MOVEABLE))
+    {
+        DWORD heap_flags = (flags & LMEM_ZEROINIT) ? HEAP_ZERO_MEMORY : 0;
+        void *ret = HeapAlloc( GetProcessHeap(), heap_flags, size );
+        TRACE( "(flags=%04x) returning %p\n",  flags, ret );
+        return ret;
+    }
     return GlobalAlloc( flags, size );
 }
 

dlls/kernel32/tests/heap.c

@@ -306,6 +306,12 @@ static void test_heap(void)
            "Expected ERROR_INVALID_HANDLE or ERROR_INVALID_PARAMETER, got %d\n", GetLastError());
     }
 
+    gbl = GlobalAlloc( GMEM_FIXED, 0 );
+    SetLastError(0xdeadbeef);
+    size = GlobalSize( gbl );
+    ok( size == 1, "wrong size %lu\n", size );
+    GlobalFree( gbl );
+
     /* ####################################### */
     /* Local*() functions */
     gbl = LocalAlloc(LMEM_MOVEABLE, 0);
@@ -438,6 +444,13 @@ static void test_heap(void)
        broken(GetLastError() == 0xdeadbeef) /* win9x */, "got %d\n", GetLastError());
     LocalFree(gbl);
 
+    gbl = LocalAlloc( LMEM_FIXED, 0 );
+    SetLastError(0xdeadbeef);
+    size = LocalSize( gbl );
+    ok( !size || broken(size == 1), /* vistau64 */
+        "wrong size %lu\n", size );
+    LocalFree( gbl );
+
     /* trying to lock empty memory should give an error */
     gbl = GlobalAlloc(GMEM_MOVEABLE|GMEM_ZEROINIT,0);
     ok(gbl != NULL, "returned NULL\n");