--- /dev/null
+#include <libguile.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+void set_flag (void *data);
+void func1 (void);
+void func2 (void);
+void func3 (void);
+void func4 (void);
+void check_flag1 (const char *msg, void (*func)(void), int val);
+SCM check_flag1_body (void *data);
+SCM return_tag (void *data, SCM tag, SCM args);
+void check_cont (int rewindable);
+SCM check_cont_body (void *data);
+
+int flag1, flag2, flag3;
+
+void
+set_flag (void *data)
+{
+ int *f = (int *)data;
+ *f = 1;
+}
+
+/* FUNC1 should leave flag1 zero.
+ */
+
+void
+func1 ()
+{
+ scm_begin_frame (0);
+ flag1 = 0;
+ scm_on_unwind (set_flag, &flag1, 0);
+ scm_end_frame ();
+}
+
+/* FUNC2 should set flag1.
+ */
+
+void
+func2 ()
+{
+ scm_begin_frame (0);
+ flag1 = 0;
+ scm_on_unwind (set_flag, &flag1, SCM_F_WIND_EXPLICITELY);
+ scm_end_frame ();
+}
+
+/* FUNC3 should set flag1.
+ */
+
+void
+func3 ()
+{
+ scm_begin_frame (0);
+ flag1 = 0;
+ scm_on_unwind (set_flag, &flag1, 0);
+ scm_misc_error ("func3", "gratuitous error", SCM_EOL);
+ scm_end_frame ();
+}
+
+/* FUNC4 should set flag1.
+ */
+
+void
+func4 ()
+{
+ scm_begin_frame (0);
+ flag1 = 0;
+ scm_on_unwind (set_flag, &flag1, SCM_F_WIND_EXPLICITELY);
+ scm_misc_error ("func4", "gratuitous error", SCM_EOL);
+ scm_end_frame ();
+}
+
+SCM
+check_flag1_body (void *data)
+{
+ void (*f)(void) = (void (*)(void))data;
+ f ();
+ return SCM_UNSPECIFIED;
+}
+
+SCM
+return_tag (void *data, SCM tag, SCM args)
+{
+ return tag;
+}
+
+void
+check_flag1 (const char *tag, void (*func)(void), int val)
+{
+ scm_internal_catch (SCM_BOOL_T,
+ check_flag1_body, func,
+ return_tag, NULL);
+ if (flag1 != val)
+ {
+ printf ("%s failed\n", tag);
+ exit (1);
+ }
+}
+
+SCM
+check_cont_body (void *data)
+{
+ scm_t_frame_flags flags = (data? SCM_F_FRAME_REWINDABLE : 0);
+ int first;
+ SCM val;
+
+ scm_begin_frame (flags);
+
+ val = scm_make_continuation (&first);
+ scm_end_frame ();
+ return val;
+}
+
+void
+check_cont (int rewindable)
+{
+ SCM res;
+
+ res = scm_internal_catch (SCM_BOOL_T,
+ check_cont_body, (void *)rewindable,
+ return_tag, NULL);
+
+ /* RES is now either the created continuation, the value passed to
+ the continuation, or a catch-tag, such as 'misc-error.
+ */
+
+ if (SCM_NFALSEP (scm_procedure_p (res)))
+ {
+ /* a continuation, invoke it */
+ scm_call_1 (res, SCM_BOOL_F);
+ }
+ else if (SCM_FALSEP (res))
+ {
+ /* the result of invoking the continuation, frame must be
+ rewindable */
+ if (rewindable)
+ return;
+ printf ("continuation not blocked\n");
+ exit (1);
+ }
+ else
+ {
+ /* the catch tag, frame must not have been rewindable. */
+ if (!rewindable)
+ return;
+ printf ("continuation didn't work\n");
+ exit (1);
+ }
+}
+
+static void
+inner_main (void *data, int argc, char **argv)
+{
+ check_flag1 ("func1", func1, 0);
+ check_flag1 ("func2", func2, 1);
+ check_flag1 ("func3", func3, 1);
+ check_flag1 ("func4", func4, 1);
+
+ check_cont (0);
+ check_cont (1);
+
+ exit (0);
+}
+
+int
+main (int argc, char **argv)
+{
+ scm_boot_guile (argc, argv, inner_main, 0);
+ return 0;
+}