[GPS]: I wanted to fetch integers from an array of [Tcl_Obj].  I didn't want to have a massive number of '''Tcl_GetIntFromObj''' polluting the flow of code.  So, I came up with this solution:
----
 /* REVISION 231 */
 #include <stdarg.h>
 #ifndef _GET_INTS_FROM_OBJS_C
 #define _GET_INTS_FROM_OBJS_C
 int
 get_ints_from_objs(Tcl_Interp *interp, Tcl_Obj *CONST objv[], int i, int end, ...) {
    va_list va;
    va_start(va, end);
    for (; i < end; ++i) {
       int *i_ptr = va_arg (va, int *);
       if (TCL_OK != Tcl_GetIntFromObj(interp, objv[i], i_ptr)) {
          va_end(va);
          return TCL_ERROR;
       }
    }
    va_end(va);
    return TCL_OK;
 }
 #endif /* _GET_INTS_FROM_OBJS_C */
----
Example usage:
 int x1, y1, x2, y2;

 if (TCL_OK != get_ints_from_objs(interp, objv, 3, 7, &x1, &y1, &x2, &y2)) {
    return TCL_ERROR;
 }
----
[DKF]: Neat.  Here are some ideas to take what you've done and make it even cooler (but not much; you've got nice work there.)
   * You might want to add some extra information to the ErrorInfo so as to state the index that failed.
   * You might want to do a variant that pulls from a List object and which does bounds-checking.
   * You might want to allow a value to be skipped by having that result pointer being NULL.