Baffling domain error on foreign call

cstring=: 3 : 'memr (>y),0,_1'
sdl2lib =: '/usr/local/lib/libSDL2.dylib'
sdlcd=: 1 : ('(''"',sdl2lib,'" '',u)&(15!:0)')

sdl_CreateWindowJ=:'SDL_CreateWindow * *c i i i i i' sdlcd

or this as a test stub in C to mimic the signature:

const char* window = "a window 0xaddress";
const char* SDL_CreateWindow(const char* title, int x, int y, int w, int h, unsigned int flags){
  return window;
}

running it...

   sdl_CreateWindowJ 'this is a test';0;0;100;200;4
sdl_CreateWindowJ 'this is a test';0;0;100;200;4
┌──────────┬──────────────┬─┬─┬───┬───┬─┐
│4304518974│this is a test│0│0│100│200│4│
└──────────┴──────────────┴─┴─┴───┴───┴─┘
   cstring=: 3 : 'memr (>y),0,_1'

cstring=: 3 : 'memr (>y),0,_1'

      cstring <4304518974
cstring <4304518974
a window 0xaddress


but then changing to use the '>' to discard the arguments and receive only the pointer...

   sdl_CreateWindowJ=:'SDL_CreateWindow > * * i i i i i' sdlcd

sdl_CreateWindowJ=:'SDL_CreateWindow > * * i i i i i' sdlcd

   sdl_CreateWindowJ 'this is a test';0;0;100;200;4

sdl_CreateWindowJ 'this is a test';0;0;100;200;4
|domain error: sdl_CreateWindowJ
|       sdl_CreateWindowJ'this is a test';0;0;100;200;4