diff --git a/align/Makefile.am b/align/Makefile.am
index 74cb2b522..cd80c191b 100644
--- a/align/Makefile.am
+++ b/align/Makefile.am
@@ -41,6 +41,7 @@ virt_alignment_scan_SOURCES = \
 
 virt_alignment_scan_CFLAGS = \
 	-DGUESTFS_WARN_DEPRECATED=1 \
+	-DGUESTFS_PRIVATE_FUNCTIONS=1 \
 	-I$(top_srcdir)/src -I$(top_builddir)/src \
 	-I$(top_srcdir)/fish \
 	-I$(srcdir)/../gnulib/lib -I../gnulib/lib \
diff --git a/align/domains.c b/align/domains.c
index 1f03fd398..e76dee95c 100644
--- a/align/domains.c
+++ b/align/domains.c
@@ -30,10 +30,6 @@
 
 #include "progname.h"
 
-#if defined(HAVE_LIBVIRT) && defined(HAVE_LIBXML2)
-#define GUESTFS_PRIVATE_FOR_EACH_DISK 1
-#endif
-
 #include "guestfs.h"
 #include "options.h"
 #include "scan.h"
diff --git a/df/Makefile.am b/df/Makefile.am
index f52d275d5..eeec48498 100644
--- a/df/Makefile.am
+++ b/df/Makefile.am
@@ -44,6 +44,7 @@ virt_df_SOURCES = \
 
 virt_df_CFLAGS = \
 	-DGUESTFS_WARN_DEPRECATED=1 \
+	-DGUESTFS_PRIVATE_FUNCTIONS=1 \
 	-I$(top_srcdir)/src -I$(top_builddir)/src \
 	-I$(top_srcdir)/fish \
 	-I$(srcdir)/../gnulib/lib -I../gnulib/lib \
diff --git a/df/domains.c b/df/domains.c
index d125ba23b..505bf2273 100644
--- a/df/domains.c
+++ b/df/domains.c
@@ -30,10 +30,6 @@
 
 #include "progname.h"
 
-#if defined(HAVE_LIBVIRT) && defined(HAVE_LIBXML2)
-#define GUESTFS_PRIVATE_FOR_EACH_DISK 1
-#endif
-
 #include "guestfs.h"
 #include "options.h"
 #include "virt-df.h"
diff --git a/examples/guestfs-performance.pod b/examples/guestfs-performance.pod
index e005813c9..e00f3dd30 100644
--- a/examples/guestfs-performance.pod
+++ b/examples/guestfs-performance.pod
@@ -368,9 +368,9 @@ example:
  xxxx (+0):	guestfs_create 
  xxxx (+29):	guestfs_set_pgroup g=0x17a9de0 pgroup=0x1
  xxxx (+9):	guestfs_add_drive_opts_argv g=0x17a9de0 [...]
- xxxx (+8):	guestfs_safe_strdup g=0x17a9de0 str=0x7f8a153bed5d
- xxxx (+19):	guestfs_safe_malloc g=0x17a9de0 nbytes=0x38
- xxxx (+5):	guestfs_safe_strdup g=0x17a9de0 str=0x17a9f60
+ xxxx (+8):	guestfs___safe_strdup g=0x17a9de0 str=0x7f8a153bed5d
+ xxxx (+19):	guestfs___safe_malloc g=0x17a9de0 nbytes=0x38
+ xxxx (+5):	guestfs___safe_strdup g=0x17a9de0 str=0x17a9f60
  xxxx (+10):	guestfs_launch g=0x17a9de0
  xxxx (+4):	launch_start 
  [etc]
diff --git a/generator/c.ml b/generator/c.ml
index f2dd1bcfd..b9d4b3566 100644
--- a/generator/c.ml
+++ b/generator/c.ml
@@ -677,20 +677,23 @@ extern GUESTFS_DLL_PUBLIC void *guestfs_next_private (guestfs_h *g, const char *
 
   pr "\
 
+#if GUESTFS_PRIVATE_FUNCTIONS
+
 /* Private functions.
  *
  * These are NOT part of the public, stable API, and can change at any
  * time!  We export them because they are used by some of the language
  * bindings.
  */
-extern GUESTFS_DLL_PUBLIC void *guestfs_safe_malloc (guestfs_h *g, size_t nbytes);
-extern GUESTFS_DLL_PUBLIC void *guestfs_safe_calloc (guestfs_h *g, size_t n, size_t s);
-extern GUESTFS_DLL_PUBLIC char *guestfs_safe_strdup (guestfs_h *g, const char *str);
-extern GUESTFS_DLL_PUBLIC void *guestfs_safe_memdup (guestfs_h *g, const void *ptr, size_t size);
-#ifdef GUESTFS_PRIVATE_FOR_EACH_DISK
-extern GUESTFS_DLL_PUBLIC int guestfs___for_each_disk (guestfs_h *g, virDomainPtr dom, int (*)(guestfs_h *g, const char *filename, const char *format, int readonly, void *data), void *data);
-#endif
-/* End of private functions. */
+
+extern GUESTFS_DLL_PUBLIC void *guestfs___safe_malloc (guestfs_h *g, size_t nbytes);
+extern GUESTFS_DLL_PUBLIC void *guestfs___safe_calloc (guestfs_h *g, size_t n, size_t s);
+extern GUESTFS_DLL_PUBLIC char *guestfs___safe_strdup (guestfs_h *g, const char *str);
+extern GUESTFS_DLL_PUBLIC void *guestfs___safe_memdup (guestfs_h *g, const void *ptr, size_t size);
+
+extern GUESTFS_DLL_PUBLIC int guestfs___for_each_disk (guestfs_h *g, /* virDomainPtr */ void *dom, int (*)(guestfs_h *g, const char *filename, const char *format, int readonly, void *data), void *data);
+
+#endif /* End of private functions. */
 
 #ifdef __cplusplus
 }
@@ -1594,10 +1597,10 @@ and generate_linker_script () =
     (* Unofficial parts of the API: the bindings code use these
      * functions, so it is useful to export them.
      *)
-    "guestfs_safe_calloc";
-    "guestfs_safe_malloc";
-    "guestfs_safe_strdup";
-    "guestfs_safe_memdup";
+    "guestfs___safe_calloc";
+    "guestfs___safe_malloc";
+    "guestfs___safe_strdup";
+    "guestfs___safe_memdup";
     "guestfs___for_each_disk";
   ] in
   let functions =
diff --git a/generator/java.ml b/generator/java.ml
index a8eea1aea..c83bf80f8 100644
--- a/generator/java.ml
+++ b/generator/java.ml
@@ -622,7 +622,7 @@ Java_com_redhat_et_libguestfs_GuestFS__1close
             pr "  %s_size = (*env)->GetArrayLength (env, j%s);\n" n n
         | StringList n | DeviceList n ->
             pr "  %s_len = (*env)->GetArrayLength (env, j%s);\n" n n;
-            pr "  %s = guestfs_safe_malloc (g, sizeof (char *) * (%s_len+1));\n" n n;
+            pr "  %s = guestfs___safe_malloc (g, sizeof (char *) * (%s_len+1));\n" n n;
             pr "  for (i = 0; i < %s_len; ++i) {\n" n;
             pr "    jobject o = (*env)->GetObjectArrayElement (env, j%s, i);\n"
               n;
@@ -648,7 +648,7 @@ Java_com_redhat_et_libguestfs_GuestFS__1close
                 n n
           | OStringList n ->
             pr "  %s_len = (*env)->GetArrayLength (env, j%s);\n" n n;
-            pr "  %s = guestfs_safe_malloc (g, sizeof (char *) * (%s_len+1));\n" n n;
+            pr "  %s = guestfs___safe_malloc (g, sizeof (char *) * (%s_len+1));\n" n n;
             pr "  for (i = 0; i < %s_len; ++i) {\n" n;
             pr "    jobject o = (*env)->GetObjectArrayElement (env, j%s, i);\n"
               n;
diff --git a/generator/ocaml.ml b/generator/ocaml.ml
index f9ac5ca5e..1ecdea812 100644
--- a/generator/ocaml.ml
+++ b/generator/ocaml.ml
@@ -503,14 +503,14 @@ copy_table (char * const * argv)
         | FileOut n
         | Key n ->
             (* Copy strings in case the GC moves them: RHBZ#604691 *)
-            pr "  char *%s = guestfs_safe_strdup (g, String_val (%sv));\n" n n
+            pr "  char *%s = guestfs___safe_strdup (g, String_val (%sv));\n" n n
         | OptString n ->
             pr "  char *%s =\n" n;
             pr "    %sv != Val_int (0) ?\n" n;
-            pr "      guestfs_safe_strdup (g, String_val (Field (%sv, 0))) : NULL;\n" n
+            pr "      guestfs___safe_strdup (g, String_val (Field (%sv, 0))) : NULL;\n" n
         | BufferIn n ->
             pr "  size_t %s_size = caml_string_length (%sv);\n" n n;
-            pr "  char *%s = guestfs_safe_memdup (g, String_val (%sv), %s_size);\n" n n n
+            pr "  char *%s = guestfs___safe_memdup (g, String_val (%sv), %s_size);\n" n n n
         | StringList n | DeviceList n ->
             pr "  char **%s = ocaml_guestfs_strings_val (g, %sv);\n" n n
         | Bool n ->
@@ -539,7 +539,7 @@ copy_table (char * const * argv)
              | OInt _ -> pr "Int_val (Field (%sv, 0))" n
              | OInt64 _ -> pr "Int64_val (Field (%sv, 0))" n
              | OString _ ->
-                 pr "guestfs_safe_strdup (g, String_val (Field (%sv, 0)))" n
+                 pr "guestfs___safe_strdup (g, String_val (Field (%sv, 0)))" n
              | OStringList n ->
                  pr "ocaml_guestfs_strings_val (g, Field (%sv, 0))\n" n
             );
diff --git a/generator/perl.ml b/generator/perl.ml
index b4c4caf4b..aa5ca260c 100644
--- a/generator/perl.ml
+++ b/generator/perl.ml
@@ -170,7 +170,7 @@ get_all_event_callbacks (guestfs_h *g, size_t *len_rtn)
   }
 
   /* Copy them into the return array. */
-  r = guestfs_safe_malloc (g, sizeof (SV *) * (*len_rtn));
+  r = guestfs___safe_malloc (g, sizeof (SV *) * (*len_rtn));
 
   i = 0;
   cb = guestfs_first_private (g, &key);
@@ -458,7 +458,7 @@ user_cancel (g)
                pr "          /* Note av_len returns index of final element. */\n";
                pr "          len = av_len (av) + 1;\n";
                pr "\n";
-               pr "          r = guestfs_safe_malloc (g, (len+1) * sizeof (char *));\n";
+               pr "          r = guestfs___safe_malloc (g, (len+1) * sizeof (char *));\n";
                pr "          for (i = 0; i < len; ++i) {\n";
                pr "            svp = av_fetch (av, i, 0);\n";
                pr "            r[i] = SvPV_nolen (*svp);\n";
diff --git a/generator/ruby.ml b/generator/ruby.ml
index 6cc17fc20..daf94a5c9 100644
--- a/generator/ruby.ml
+++ b/generator/ruby.ml
@@ -207,7 +207,7 @@ ruby_set_event_callback (VALUE gv, VALUE cbv, VALUE event_bitmaskv)
 
   event_bitmask = NUM2ULL (event_bitmaskv);
 
-  root = guestfs_safe_malloc (g, sizeof *root);
+  root = guestfs___safe_malloc (g, sizeof *root);
   *root = cbv;
 
   eh = guestfs_set_event_callback (g, ruby_event_callback_wrapper,
@@ -352,7 +352,7 @@ get_all_event_callbacks (guestfs_h *g, size_t *len_rtn)
   }
 
   /* Copy them into the return array. */
-  r = guestfs_safe_malloc (g, sizeof (VALUE *) * (*len_rtn));
+  r = guestfs___safe_malloc (g, sizeof (VALUE *) * (*len_rtn));
 
   i = 0;
   root = guestfs_first_private (g, &key);
diff --git a/java/Makefile.am b/java/Makefile.am
index 3ce593bd3..b655ae9c1 100644
--- a/java/Makefile.am
+++ b/java/Makefile.am
@@ -77,9 +77,10 @@ libguestfs_jni_la_SOURCES = \
 libguestfs_jni_la_LIBADD = $(top_builddir)/src/libguestfs.la
 libguestfs_jni_la_LDFLAGS = -version-info $(JNI_VERSION_INFO) -shared
 libguestfs_jni_la_CFLAGS = \
-  $(WARN_CFLAGS) $(WERROR_CFLAGS) \
-  -I$(top_srcdir)/src -I$(top_builddir)/src \
-  $(JNI_CFLAGS)
+	-DGUESTFS_PRIVATE_FUNCTIONS=1 \
+	$(WARN_CFLAGS) $(WERROR_CFLAGS) \
+	-I$(top_srcdir)/src -I$(top_builddir)/src \
+	$(JNI_CFLAGS)
 
 BUILT_SOURCES = com_redhat_et_libguestfs_GuestFS.h
 
diff --git a/ocaml/Makefile.am b/ocaml/Makefile.am
index a17f6166e..3bd2a7841 100644
--- a/ocaml/Makefile.am
+++ b/ocaml/Makefile.am
@@ -64,6 +64,7 @@ mlguestfs.cmxa: libguestfsocaml.a guestfs.cmx
 	  -L$(top_builddir)/src/.libs -lguestfs
 
 libguestfsocaml_a_CFLAGS = \
+	-DGUESTFS_PRIVATE_FUNCTIONS=1 \
 	-I$(top_builddir) -I$(OCAMLLIB) -I$(top_srcdir)/ocaml \
 	-I$(top_srcdir)/src -I$(top_builddir)/src \
 	$(WARN_CFLAGS) $(WERROR_CFLAGS) \
diff --git a/ocaml/guestfs-c.c b/ocaml/guestfs-c.c
index 90eea547e..0b3369fd5 100644
--- a/ocaml/guestfs-c.c
+++ b/ocaml/guestfs-c.c
@@ -168,7 +168,7 @@ ocaml_guestfs_create (value environmentv, value close_on_exitv, value unitv)
   /* Store the OCaml handle into the C handle.  This is only so we can
    * map the C handle to the OCaml handle in event_callback_wrapper.
    */
-  v = guestfs_safe_malloc (g, sizeof *v);
+  v = guestfs___safe_malloc (g, sizeof *v);
   *v = gv;
   /* XXX This global root is generational, but we cannot rely on every
    * user having the OCaml 3.11 version which supports this.
@@ -201,9 +201,9 @@ ocaml_guestfs_strings_val (guestfs_h *g, value sv)
   char **r;
   size_t i;
 
-  r = guestfs_safe_malloc (g, sizeof (char *) * (Wosize_val (sv) + 1));
+  r = guestfs___safe_malloc (g, sizeof (char *) * (Wosize_val (sv) + 1));
   for (i = 0; i < Wosize_val (sv); ++i)
-    r[i] = guestfs_safe_strdup (g, String_val (Field (sv, i)));
+    r[i] = guestfs___safe_strdup (g, String_val (Field (sv, i)));
   r[i] = NULL;
 
   CAMLreturnT (char **, r);
@@ -246,7 +246,7 @@ ocaml_guestfs_set_event_callback (value gv, value closure, value events)
 
   event_bitmask = event_bitmask_of_event_list (events);
 
-  value *root = guestfs_safe_malloc (g, sizeof *root);
+  value *root = guestfs___safe_malloc (g, sizeof *root);
   *root = closure;
 
   eh = guestfs_set_event_callback (g, event_callback_wrapper,
@@ -309,7 +309,7 @@ get_all_event_callbacks (guestfs_h *g, size_t *len_rtn)
   }
 
   /* Copy them into the return array. */
-  r = guestfs_safe_malloc (g, sizeof (value *) * (*len_rtn));
+  r = guestfs___safe_malloc (g, sizeof (value *) * (*len_rtn));
 
   i = 0;
   root = guestfs_first_private (g, &key);
diff --git a/perl/Makefile.PL.in b/perl/Makefile.PL.in
index 9fbeb4572..11a976a4d 100644
--- a/perl/Makefile.PL.in
+++ b/perl/Makefile.PL.in
@@ -27,5 +27,5 @@ WriteMakefile (
     LIBS => '-L@top_builddir@/src/.libs -lguestfs',
     INC => '-I@top_builddir@/src -I@top_srcdir@/src',
     TYPEMAPS => [ '@srcdir@/typemap' ],
-    CCFLAGS => $Config{ccflags} . ' @CFLAGS@',
+    CCFLAGS => $Config{ccflags} . ' -DGUESTFS_PRIVATE_FUNCTIONS=1 @CFLAGS@',
     );
diff --git a/python/Makefile.am b/python/Makefile.am
index 84941b301..8000f1c69 100644
--- a/python/Makefile.am
+++ b/python/Makefile.am
@@ -40,8 +40,11 @@ python_DATA = guestfs.py
 python_LTLIBRARIES = libguestfsmod.la
 
 libguestfsmod_la_SOURCES = guestfs-py.c guestfs-py.h guestfs-py-byhand.c
-libguestfsmod_la_CFLAGS = -Wall -I$(PYTHON_INCLUDEDIR) \
-			  -I$(top_srcdir)/src -I$(top_builddir)/src
+libguestfsmod_la_CFLAGS = \
+	-DGUESTFS_PRIVATE_FUNCTIONS=1 \
+	-Wall \
+	-I$(PYTHON_INCLUDEDIR) \
+	-I$(top_srcdir)/src -I$(top_builddir)/src
 libguestfsmod_la_LIBADD = $(top_builddir)/src/libguestfs.la
 libguestfsmod_la_LDFLAGS = -avoid-version -shared
 
diff --git a/python/guestfs-py-byhand.c b/python/guestfs-py-byhand.c
index 6cbbf5064..5edaaf2da 100644
--- a/python/guestfs-py-byhand.c
+++ b/python/guestfs-py-byhand.c
@@ -219,7 +219,7 @@ get_all_event_callbacks (guestfs_h *g, size_t *len_rtn)
   }
 
   /* Copy them into the return array. */
-  r = guestfs_safe_malloc (g, sizeof (PyObject *) * (*len_rtn));
+  r = guestfs___safe_malloc (g, sizeof (PyObject *) * (*len_rtn));
 
   i = 0;
   cb = guestfs_first_private (g, &key);
diff --git a/src/Makefile.am b/src/Makefile.am
index dafc48819..1057245b3 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -195,6 +195,7 @@ libguestfs_la_LIBADD += liberrnostring.la libprotocol.la
 libguestfs_la_CFLAGS = \
 	-DGUESTFS_DEFAULT_PATH='"$(libdir)/guestfs"' \
 	-DGUESTFS_WARN_DEPRECATED=1 \
+	-DGUESTFS_PRIVATE_FUNCTIONS=1 \
 	-DLIBOSINFO_DB_PATH='"$(datadir)/libosinfo/db"' \
 	$(WARN_CFLAGS) $(WERROR_CFLAGS) \
 	$(GPROF_CFLAGS) $(GCOV_CFLAGS) \
diff --git a/src/alloc.c b/src/alloc.c
index dc64bbd8c..25d7f428c 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -27,7 +27,7 @@
 #include "guestfs-internal.h"
 
 void *
-guestfs_safe_malloc (guestfs_h *g, size_t nbytes)
+guestfs___safe_malloc (guestfs_h *g, size_t nbytes)
 {
   void *ptr = malloc (nbytes);
   if (nbytes > 0 && !ptr) g->abort_cb ();
@@ -60,7 +60,7 @@ guestfs_safe_malloc (guestfs_h *g, size_t nbytes)
 /* Allocate zeroed memory for N elements of S bytes, with error
    checking.  S must be nonzero.  */
 void *
-guestfs_safe_calloc (guestfs_h *g, size_t n, size_t s)
+guestfs___safe_calloc (guestfs_h *g, size_t n, size_t s)
 {
   /* From gnulib's calloc function in xmalloc.c.  */
   void *p;
@@ -75,7 +75,7 @@ guestfs_safe_calloc (guestfs_h *g, size_t n, size_t s)
 }
 
 void *
-guestfs_safe_realloc (guestfs_h *g, void *ptr, size_t nbytes)
+guestfs___safe_realloc (guestfs_h *g, void *ptr, size_t nbytes)
 {
   void *p = realloc (ptr, nbytes);
   if (nbytes > 0 && !p) g->abort_cb ();
@@ -83,7 +83,7 @@ guestfs_safe_realloc (guestfs_h *g, void *ptr, size_t nbytes)
 }
 
 char *
-guestfs_safe_strdup (guestfs_h *g, const char *str)
+guestfs___safe_strdup (guestfs_h *g, const char *str)
 {
   char *s = strdup (str);
   if (!s) g->abort_cb ();
@@ -91,7 +91,7 @@ guestfs_safe_strdup (guestfs_h *g, const char *str)
 }
 
 char *
-guestfs_safe_strndup (guestfs_h *g, const char *str, size_t n)
+guestfs___safe_strndup (guestfs_h *g, const char *str, size_t n)
 {
   char *s = strndup (str, n);
   if (!s) g->abort_cb ();
@@ -99,7 +99,7 @@ guestfs_safe_strndup (guestfs_h *g, const char *str, size_t n)
 }
 
 void *
-guestfs_safe_memdup (guestfs_h *g, const void *ptr, size_t size)
+guestfs___safe_memdup (guestfs_h *g, const void *ptr, size_t size)
 {
   void *p = malloc (size);
   if (!p) g->abort_cb ();
@@ -108,7 +108,7 @@ guestfs_safe_memdup (guestfs_h *g, const void *ptr, size_t size)
 }
 
 char *
-guestfs_safe_asprintf (guestfs_h *g, const char *fs, ...)
+guestfs___safe_asprintf (guestfs_h *g, const char *fs, ...)
 {
   va_list args;
   char *msg;
diff --git a/src/events.c b/src/events.c
index 947422834..67dba2333 100644
--- a/src/events.c
+++ b/src/events.c
@@ -57,8 +57,8 @@ guestfs_set_event_callback (guestfs_h *g,
 
   int event_handle = (int) g->nr_events;
   g->events =
-    guestfs_safe_realloc (g, g->events,
-                          (g->nr_events+1) * sizeof (struct event));
+    safe_realloc (g, g->events,
+                  (g->nr_events+1) * sizeof (struct event));
   g->nr_events++;
 
   g->events[event_handle].event_bitmask = event_bitmask;
@@ -242,8 +242,8 @@ replace_old_style_event_callback (guestfs_h *g,
 
   /* i == g->nr_events */
   g->events =
-    guestfs_safe_realloc (g, g->events,
-                          (g->nr_events+1) * sizeof (struct event));
+    safe_realloc (g, g->events,
+                  (g->nr_events+1) * sizeof (struct event));
   g->nr_events++;
 
  replace:
diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
index df52f7427..870207bd7 100644
--- a/src/guestfs-internal.h
+++ b/src/guestfs-internal.h
@@ -459,20 +459,20 @@ struct guestfs_message_error;
 struct guestfs_progress;
 
 /* alloc.c */
-extern void *guestfs_safe_realloc (guestfs_h *g, void *ptr, size_t nbytes);
-extern char *guestfs_safe_strdup (guestfs_h *g, const char *str);
-extern char *guestfs_safe_strndup (guestfs_h *g, const char *str, size_t n);
-extern void *guestfs_safe_memdup (guestfs_h *g, const void *ptr, size_t size);
-extern char *guestfs_safe_asprintf (guestfs_h *g, const char *fs, ...)
+extern void *guestfs___safe_realloc (guestfs_h *g, void *ptr, size_t nbytes);
+extern char *guestfs___safe_strdup (guestfs_h *g, const char *str);
+extern char *guestfs___safe_strndup (guestfs_h *g, const char *str, size_t n);
+extern void *guestfs___safe_memdup (guestfs_h *g, const void *ptr, size_t size);
+extern char *guestfs___safe_asprintf (guestfs_h *g, const char *fs, ...)
   __attribute__((format (printf,2,3)));
 
-#define safe_calloc guestfs_safe_calloc
-#define safe_malloc guestfs_safe_malloc
-#define safe_realloc guestfs_safe_realloc
-#define safe_strdup guestfs_safe_strdup
-#define safe_strndup guestfs_safe_strndup
-#define safe_memdup guestfs_safe_memdup
-#define safe_asprintf guestfs_safe_asprintf
+#define safe_calloc guestfs___safe_calloc
+#define safe_malloc guestfs___safe_malloc
+#define safe_realloc guestfs___safe_realloc
+#define safe_strdup guestfs___safe_strdup
+#define safe_strndup guestfs___safe_strndup
+#define safe_memdup guestfs___safe_memdup
+#define safe_asprintf guestfs___safe_asprintf
 
 /* errors.c */
 extern void guestfs___init_error_handler (guestfs_h *g);
diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index f65686ce5..8d3804dfb 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -33,10 +33,6 @@
 #include <libxml/tree.h>
 #endif
 
-#if defined(HAVE_LIBVIRT) && defined(HAVE_LIBXML2)
-#define GUESTFS_PRIVATE_FOR_EACH_DISK 1
-#endif
-
 #include "guestfs.h"
 #include "guestfs-internal.h"
 #include "guestfs-internal-actions.h"
@@ -161,16 +157,20 @@ guestfs__add_domain (guestfs_h *g, const char *domain_name,
  * The callback function 'f' is called once for each disk.
  *
  * Returns number of disks, or -1 if there was an error.
+ *
+ * 'domv' is declared void* for convenience so it can appear as a
+ * private function in the public <guestfs.h> header.
  */
 int
 guestfs___for_each_disk (guestfs_h *g,
-                         virDomainPtr dom,
+                         void *domv,
                          int (*f) (guestfs_h *g,
                                    const char *filename, const char *format,
                                    int readonly,
                                    void *data),
                          void *data)
 {
+  virDomainPtr dom = domv;
   int i, nr_added = 0, r = -1;
   virErrorPtr err;
   xmlDocPtr doc = NULL;