bson_iter_init - Man Page

bool
bson_iter_init (bson_iter_t *iter, const bson_t *bson);

• iter: A bson_iter_t.
• bson: A bson_t.

The bson_iter_init() function shall initialize iter to iterate upon the BSON document bson. Upon initialization, iter is placed before the first element. Callers must call bson_iter_next(), bson_iter_find(), or bson_iter_find_case() to advance to an element.

Returns true if the iter was successfully initialized.

static void
print_doc_id (const bson_t *doc)
{
   bson_iter_t iter;
   bson_oid_t oid;
   char oidstr[25];

   if (bson_iter_init (&iter, doc) && bson_iter_find (&iter, "_id") &&
       BSON_ITER_HOLDS_OID (&iter)) {
      bson_iter_oid (&iter, &oid);
      bson_oid_to_string (&oid, oidstr);
      printf ("%s\n", oidstr);
   } else {
      printf ("Document is missing _id.\n");
   }
}

/* alternatively */

static void
print_doc_id (const bson_t *doc)
{
   bson_iter_t iter;
   bson_oid_t oid;
   char oidstr[25];

   if (bson_iter_init_find (&iter, doc, "_id") && BSON_ITER_HOLDS_OID (&iter)) {
      bson_iter_oid (&iter, &oid);
      bson_oid_to_string (&oid, oidstr);
      printf ("%s\n", oidstr);
   } else {
      printf ("Document is missing _id.\n");
   }
}

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