Add `mrb_alloca` again; ref
This time, the allocated memory comes from the string object, which is
referenced from GC arena. The memory region will be reclaimed when the C
function called from VM is terminated, or the GC arena is restored.
MODIFY
include/mruby.h
include/mruby.h
@@ -1246,6 +1246,8 @@ MRB_API void mrb_pool_close(struct mrb_pool*);
MRB_API void* mrb_pool_alloc(struct mrb_pool*, size_t);
MRB_API void* mrb_pool_realloc(struct mrb_pool*, void*, size_t oldlen, size_t newlen);
MRB_API mrb_bool mrb_pool_can_realloc(struct mrb_pool*, void*, size_t);
+/* temporary memory allocation, only effective while GC arena is kept */
+MRB_API void* mrb_alloca(mrb_state *mrb, size_t);
MRB_API void mrb_state_atexit(mrb_state *mrb, mrb_atexit_func func);

MODIFY
src/gc.c
src/gc.c
@@ -277,6 +277,13 @@ mrb_free(mrb_state *mrb, void *p)
(mrb->allocf)(mrb, p, 0, mrb->allocf_ud);
}
+MRB_API void*
+mrb_alloca(mrb_state *mrb, size_t size)
+{
+ mrb_value str = mrb_str_new(mrb, NULL, size);
+ return RSTRING_PTR(str);
+}
+
static mrb_bool
heap_p(mrb_gc *gc, struct RBasic *object)
{

Add `mrb_alloca` again; ref #4470

This time, the allocated memory comes from the string object, which is
referenced from GC arena. The memory region will be reclaimed when the C
function called from VM is terminated, or the GC arena is restored.