Add new User Pointer (User_Ptr) type

* src/lisp.h: Add new Lisp_Misc_User_Ptr type.
(XUSER_PTR): New User_Ptr accessor.
* src/alloc.c (make_user_ptr): New function.
(mark_object, sweep_misc): Handle Lisp_Misc_User_Ptr.
* src/data.c (Ftype_of): Return 'user-ptr' for user pointer.
(Fuser-ptrp): New user pointer type predicate function.
(syms_of_data): New 'user-ptrp', 'user-ptr' symbol.  New 'user-ptrp'
subr.
* src/print.c (print_object): Add printer for User_Ptr type.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/print.c b/src/print.c
index 6f868ceff84..420e6f55b4c 100644
--- a/src/print.c
+++ b/src/print.c
@@ -1990,6 +1990,19 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag)
           printchar ('>', printcharfun);
           break;
 
+#ifdef HAVE_MODULES
+        case Lisp_Misc_User_Ptr:
+          {
+            print_c_string ("#<user-ptr ", printcharfun);
+            int i = sprintf (buf, "ptr=%p finalizer=%p",
+                             XUSER_PTR (obj)->p,
+                             XUSER_PTR (obj)->finalizer);
+            strout (buf, i, i, printcharfun);
+            printchar ('>', printcharfun);
+            break;
+          }
+#endif
+
         case Lisp_Misc_Finalizer:
           print_c_string ("#<finalizer", printcharfun);
           if (NILP (XFINALIZER (obj)->function))