+ verify_true is obsolescent; please use verify_expr instead. */
+
+# define verify_true(R) _GL_VERIFY_TRUE (R, "verify_true (" #R ")")
+
+/* Verify requirement R at compile-time. Return the value of the
+ expression E. */
+
+# define verify_expr(R, E) \
+ (_GL_VERIFY_TRUE (R, "verify_expr (" #R ", " #E ")") ? (E) : (E))