#include <mongoc.h>

typedef struct
   bool                        is_initialized;
   bool                        background;
   bool                        unique;
   const char                 *name;
   bool                        drop_dups;
   bool                        sparse;
   int32_t                     expire_after_seconds;
   int32_t                     v;
   const bson_t               *weights;
   const char                 *default_language;
   const char                 *language_override;
   mongoc_index_opt_geo_t     *geo_options;
   mongoc_index_opt_storage_t *storage_options;
   void                       *padding[6];
} mongoc_index_opt_t;


This structure contains the options that may be used for tuning a specific index.

NOTE: dropDups is deprecated as of MongoDB version 2.7.5. This option is silently ignored by the server and unique index builds using this option will fail if a duplicate value is detected.