+/* --- @tvec_parsedurunit@ --- *
+ *
+ * Arguments: @double *scale_out@ = where to leave the scale
+ * @const char **p_inout@ = input unit string, updated
+ *
+ * Returns: Zero on success, %$-1$% on error.
+ *
+ * Use: If @*p_inout@ begins with a unit string followed by the end
+ * of the string or some non-alphanumeric character, then store
+ * the corresponding scale factor in @*scale_out@, advance
+ * @*p_inout@ past the unit string, and return zero. Otherwise,
+ * return %$-1$%.
+ */
+
+extern int tvec_parsedurunit(double */*scale_out*/,
+ const char **/*p_inout*/);
+