typedef __code (*csPtr)(__rectype);

//typedef __code (*csPtr)(__code(*p)());
//typedef __code (csPtr)(__code(*p)()); // csPtr *p

#include <stdio.h>
__code cs_end(csPtr p)
{
  printf("end\n");
}

__code cs(csPtr p)
{
  csPtr b;
  goto p(b);
  //  goto p(3); // note: expected ‘void (*)()’ but argument is of type ‘int’
}

int main() {
  csPtr p;
  p = cs_end;
  goto cs(p);
  return 0;
}