Accessing an element at an index from an array of structs through c-ref

[ghost]

From the c-plus examples:

(c-ref object foo-t :a)              ;; => object.a
(c-ref object foo-t :c 2)            ;; => object.c[2]
(c-ref object foo-t :x 2 :b0)        ;; => object.x[2].b0
(c-ref object foo-t :x :b0)          ;; => object.x[0].b0
(c-ref object foo-t :c *)            ;; => *(object.c)
(c-ref object foo-t :x 1 :s :x &)    ;; => &(object.x[1].s.x)

Is there a simpler way to access an element at an index from an array of structs?

(...)              ;; => object[1].a

Currently, I get a pointer first using c-aptr:

(c-with ((iovec (:struct (c:iovec)) :count 2))
      (c-ref (c-aptr iovec 0 '(:struct (c:iovec))) ;; pointer to struct at index 0
             (:struct (c:iovec)) ;; pointer type
             :iov-len)) ;; member

A cleaner way would be something like:

(c-with ((iovec (:struct (c:iovec)) :count 2))
      (iovec :index 0 :iov-len))

[rpav]

Does a number in the first position not work? I.e., (iovec 0 :iov-len)?

[ghost]

The c-with macro has the keyword count, however the c-ref macro does not. The c-ref macro can only access an index of a member array of a struct, but not an array of structs.

(plus-c:c-with ((iovec (:struct (c:iovec)) :count 2))
      (iovec 0 :iov-len))
; in: PLUS-C:C-WITH ((IOVEC (:STRUCT (C:IOVEC)) :COUNT 2))
;     (IOVEC 0 :IOV-LEN)
; ==>
;   (PLUS-C:C-REF #:TMP951 (:STRUCT (C:IOVEC)) 0 :IOV-LEN)
; 
; caught ERROR:
;   during macroexpansion of (PLUS-C:C-REF #:TMP951 (:STRUCT #) ...). Use
;   *BREAK-ON-SIGNALS* to intercept.
;   
;    Error parsing ref: 0 on type #<AUTOWRAP:FOREIGN-RECORD IOVEC {1002173723}>
; 
; compilation unit finished
;   caught 1 ERROR condition

debugger invoked on a SB-INT:COMPILED-PROGRAM-ERROR in thread
#<THREAD "main thread" RUNNING {100301E883}>:
  Execution of a form compiled with errors.
Form:
  (PLUS-C:C-REF #:TMP951 (:STRUCT (C:IOVEC)) 0 :IOV-LEN)
Compile-time error:
  during macroexpansion of (PLUS-C:C-REF #:TMP951 (:STRUCT #) ...). Use
*BREAK-ON-SIGNALS* to intercept.

 Error parsing ref: 0 on type #<AUTOWRAP:FOREIGN-RECORD IOVEC {1002173723}>

Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [ABORT] Exit debugger, returning to top level.

((LAMBDA ()))
   source: (IOVEC 0 :IOV-LEN)
0]