I'm a bit careful and general in my reply because I don't know the library you
use. First, in Nim an array has a known and fixed size. If you need a dynamic
array have a lot of seq.
Basically you should differentiate between two cases:
* 1) The C func has a size parameter directly following the array/pointer
(typically of type size_t)
* 2) The C func does not have a size parameter directly following
Examples for both would be
// type 1, with size
int foo1(char *bar, int bsize); // 'bsize' is the number of chars in 'bar'
// type 2, no size
int foo2(char *bar);
Run
The proper declaration and calling of those funcs in/from Nim:
proc foo1(arr: openarray[char]): cint {.importc.}
proc foo2(arr: ptr char): cint {.importc.}
#...
var myArr: array[42, char]
let res1 = foo1(myArr)
let res2 = foo2(addr(myArr[0]))
Run
Note that Nim automagically passes both, a ptr to the array data and the size
of the array to a C func declared to have an `openarray` parameter.
In your case - and assuming `imgdata` has a fixed size, e.g. 10 - something
like this
type
Image = object
# fields
Ihandle = ptr Image
proc iupImageRGBA(p1, p2: cint; imgArr: ptr byte): Ihandle {.importc.}
var imgdata = [0'byte, 0, 0, 0, 0, 0, 0, 0, 0, 0] # fixed size! array
var image: Ihandle = iupImageRGBA(32, 32, addr(imgdata[0]))
Run
should do what you want.
Warning: my example is based on certain assumptions (e.g. the first 2
parameters being of type cint). I strongly suggest to make the effort of
providing all needed info when asking questions to avoid misunderstandings.
