simplistic wrapping of https://github.com/osqp/osqp/blob/master/include/types.h#L21

ffi-pointers.rkt

#lang racket/base

(require ffi/unsafe)

(define-cstruct _csc
  ([nzmax _int]     ; ///< maximum number of entries
   [m     _int]     ; ///< number of rows
   [n     _int]     ; ///< number of columns
   [p*    _pointer] ; ///< column pointers (size n+1); col indices (size nzmax)
                    ;   start from 0 when using triplet format (direct KKT
                    ;   matrix formation)
   [i*    _pointer] ; ///< row indices, size nzmax starting from 0
   [x*    _pointer] ; ///< numerical values, size nzmax
   [nz    _int]))

;; write functions using `ptr-ref` and `ptr-set!` to access contents of p* i* x*