Unable to forward decalre incomplete type for stack

[krumlo]

Following the README I've written this code

typedef struct Point Point;

forward_cstack(cstack_pnt, Point); // declare cstack_pnt (and cstack_pnt_value, cstack_pnt_iter);
                                          // struct Point may be an incomplete type.
typedef struct Dataset {
    cstack_pnt vertices;
    cstack_pnt colors;
} Dataset;

// Implementation
#define i_is_forward                  // flag that the container was forward declared.
#define i_key Point
#define i_tag pnt
#include <stc/cstack.h>

But when I'm building I get loads of errors due to incomplete type, e.g

In file included from /home/dankru/repos/cge/src/cge/layers/layer_stack.c:28:
/home/dankru/repos/cge/vendor/STC/include/stc/cstack.h:62:48: error: invalid application of 'sizeof' to an incomplete type 'Point' (aka 'struct Point')
    _cx_self out = {(_cx_value *) i_malloc(cap*c_sizeof(i_key)), 0, cap};
                                  ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
/home/dankru/repos/cge/vendor/STC/include/stc/ccommon.h:89:43: note: expanded from macro 'c_sizeof'
#define c_sizeof                (intptr_t)sizeof
                                          ^
/home/dankru/repos/cge/vendor/STC/include/stc/ccommon.h:78:46: note: expanded from macro 'c_malloc'
#define c_malloc(sz)            malloc(c_i2u(sz))
                                       ~~~~~~^~~
/home/dankru/repos/cge/vendor/STC/include/stc/ccommon.h:98:43: note: expanded from macro 'c_i2u'
#define c_i2u(i)                ((size_t)(i) + 0*sizeof((i) == 1))
                                          ^
/home/dankru/repos/cge/src/cge/layers/layer_stack.c:15:16: note: forward declaration of 'struct Point'
typedef struct Point Point;
               ^
In file included from /home/dankru/repos/cge/src/cge/layers/layer_stack.c:28:
/home/dankru/repos/cge/vendor/STC/include/stc/cstack.h:62:48: error: invalid application of 'sizeof' to an incomplete type 'Point' (aka 'struct Point')
    _cx_self out = {(_cx_value *) i_malloc(cap*c_sizeof(i_key)), 0, cap};
                                  ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
/home/dankru/repos/cge/vendor/STC/include/stc/ccommon.h:89:43: note: expanded from macro 'c_sizeof'
#define c_sizeof                (intptr_t)sizeof
                                          ^
/home/dankru/repos/cge/vendor/STC/include/stc/ccommon.h:78:46: note: expanded from macro 'c_malloc'
#define c_malloc(sz)            malloc(c_i2u(sz))
                                       ~~~~~~^~~
/home/dankru/repos/cge/vendor/STC/include/stc/ccommon.h:98:58: note: expanded from macro 'c_i2u'
#define c_i2u(i)                ((size_t)(i) + 0*sizeof((i) == 1))
                                                         ^
/home/dankru/repos/cge/src/cge/layers/layer_stack.c:15:16: note: forward declaration of 'struct Point'
typedef struct Point Point;
               ^
In file included from /home/dankru/repos/cge/src/cge/layers/layer_stack.c:28:
/home/dankru/repos/cge/vendor/STC/include/stc/cstack.h:66:63: error: variable has incomplete type 'Point' (aka 'struct Point')
STC_INLINE _cx_self _cx_memb(_with_size)(intptr_t size, i_key null) {
                                                              ^
/home/dankru/repos/cge/src/cge/layers/layer_stack.c:15:16: note: forward declaration of 'struct Point'
typedef struct Point Point;

What am I missing? :)

[tylov]

You need to #include <stc/forward.h> before the forward_cstack() declaration. And you must define struct Point in the implementation (c file), before #include <stc/cstack.h>. I will update the docs on this, thanks.