coroutines: Added compile-time check in cco_routine(): cco member mus…

…t be first in task structs.

include/stc/coroutine.h

@@ -79,6 +79,7 @@ typedef struct {
 #define cco_active(co) ((co)->cco.state != CCO_STATE_DONE)
 
 #define cco_routine(co) \
+    _cco_check_task_struct(co); \
     for (int* _state = &(co)->cco.state; *_state != CCO_STATE_DONE; *_state = CCO_STATE_DONE) \
         _resume: switch (*_state) case CCO_STATE_INIT: // thanks, @liigo!
 
@@ -222,14 +223,20 @@ typedef struct cco_task cco_task;
 
 typedef struct cco_runtime {
     int result, top;
-    struct cco_task* stack[];
+    cco_task* stack[];
 } cco_runtime;
 
 #define cco_cast_task(task) \
-    ((struct cco_task *)(task) + 0*sizeof((task)->cco.func(task, (cco_runtime*)0) + ((int*)0 == &(task)->cco.state)))
+    ((struct cco_task *)(task) + 0*sizeof((task)->cco.func(task, (cco_runtime*)0)))
 
-#define cco_check_task_struct(name) \
-    (void)c_static_assert(offsetof(struct name, cco.func) == 0);
+#if defined __GNUC__ || _MSC_VER >= 1939
+  #define _cco_check_task_struct(co) \
+    (void)c_static_assert(/* error: cco not first member in task struct */ \
+                          (sizeof((co)->cco) == sizeof(cco_state) || \
+                           offsetof(__typeof__(*(co)), cco) == 0))
+#else
+  #define _cco_check_task_struct(co) (void)0
+#endif
 
 #define cco_resume_task(task, rt) \
     (task)->cco.func(task, rt)

misc/benchmarks/various/binsearch_bench.c

@@ -32,7 +32,7 @@ int main(int argc, char const *argv[])
           count += std::binary_search(v.data, v.data + ivec_size(&v), r);
         #else
           #define LABEL "ivec_binary_search"
-          count += ivec_binary_search(&v, r) != -1;
+          count += ivec_binary_search(&v, r) != c_NPOS;
         #endif
     }
     t = clock() - t;

misc/examples/coroutines/cotasks2.c

@@ -8,8 +8,8 @@
 
 // PRODUCER
 cco_task_struct (produce_items) {
-    produce_items_state cco; // must be first
     struct consume_items* consumer;
+    produce_items_state cco; // must be first
     Inventory inv;
     int limit, batch, serial, total;
 };
@@ -21,8 +21,6 @@ cco_task_struct (consume_items) {
 };
 
 int produce_items(struct produce_items* co, cco_runtime* rt) {
-    cco_check_task_struct(produce_items); // compile-time check that cco is first member
-
     cco_routine (co) {
         while (1) {
             if (co->serial > co->total) {
@@ -53,8 +51,6 @@ int produce_items(struct produce_items* co, cco_runtime* rt) {
 }
 
 int consume_items(struct consume_items* co, cco_runtime* rt) {
-    cco_check_task_struct(consume_items);
-
     cco_routine (co) {
         while (1) {
             int n = rand() % 10;