API Incompatibility Notes


  • The following public template types have been put into mdds::detail namespace:

    • has_value_type

    • const_or_not

    • const_t

    • get_iterator_type

    • invalid_static_int


  • In 2.0, multi_type_vector took two template parameters: one for the element block functions and one for other traits. In 2.1, multi_type_vector only takes one template parameter for the traits, and the traits now must include the element block functions.

  • The following block function helpers have been removed:

    • mdds::mtv::custom_block_func1

    • mdds::mtv::custom_block_func2

    • mdds::mtv::custom_block_func3

    They have been replaced with mdds::mtv::element_block_funcs which uses template parameter pack to allow unspecified number of standard and custom blocks.

    As a result of this change, the following headers have been removed:

    • include/mdds/multi_type_vector/custom_func1.hpp

    • include/mdds/multi_type_vector/custom_func2.hpp

    • include/mdds/multi_type_vector/custom_func3.hpp

    • include/mdds/multi_type_vector/trait.hpp

    • include/mdds/multi_type_vector_custom_func2.hpp

    • include/mdds/multi_type_vector_custom_func3.hpp

    • include/mdds/multi_type_vector_trait.hpp

  • mdds::mtv::default_trait has been renamed to mdds::mtv::default_traits.

  • The following element block types have an additional template parameter to specify the underlying storage type. This can be used to specify, for instance, whether the element block uses std::vector, std::deque or another custom container type with API compatible with the aforementioned two.

    • mdds::mtv::default_element_block

    • mdds::mtv::managed_element_block

    • mdds::mtv::noncopyable_managed_element_block

    With this change, the compiler macro named MDDS_MULTI_TYPE_VECTOR_USE_DEQUE, which was previously used to switch from std::vector to std::deque as the underlying storage type for all element blocks, has been removed.


  • mdds::mtm::std_string_trait has been renamed to mdds::mtm::std_string_traits.

trie_map / packed_trie_map

  • The following public types have been renamed:

    • mdds::trie::std_container_trait -> mdds::trie::std_container_traits

    • mdds::trie::std_string_trait -> mdds::trie::std_string_traits


  • baseline C++ version has been set to C++17.

  • deprecated rectangle_set data structure has been removed.


  • The second template parameter is now a trait type that specifies custom event function type and loop-unrolling factor. Prior to 2.0 the second template parameter was custom event function type.

  • Due to the addition of the structure-of-arrays variant, the following header files have been relocated:

    Relocated Headers

    Old header location

    New header location















    The old headers will continue to work for the time being, but consider them deprecated.

  • Since now we have array-of-structures (AoS) and structure-of-arrays (SoA) variants of multi_type_vector, there are two instances of multi_type_vector class in two different headers and namespace locations. To use the AoS variant, include the header

    #include <mdds/multi_type_vector/aos/main.hpp>

    and instantiate the template class as mdds::mtv::aos::multi_type_vector. Likewise, to use the SoA variant, include the header

    #include <mdds/multi_type_vector/soa/main.hpp>

    and instantiate the template class as mdds::mtv::soa::multi_type_vector.

    If you include the original header

    #include <mdds/multi_type_vector.hpp>

    it will include a template alias mdds::multi_type_vector that simply references mdds::mtv::soa::multi_type_vector.


  • The following public types have been renamed:

    • search_result -> search_results

    • search_result_type -> search_results_type



  • The standard integer blocks previously used non-standard integer types, namely:

    • short

    • unsigned short

    • int

    • unsigned int

    • long

    • unsigned long

    • char

    • unsigned char

    Starting with this version, the integer blocks now use:

    • (u)int8_t

    • (u)int16_t

    • (u)int32_t

    • (u)int64_t

  • The numeric_element_block type has been renamed to double_element_block, to make room for a new element block for float type named float_element_block.



  • The walk() methods previously took the function object by reference, but the newer versions now take the function object by value. With this change, it is now possible to pass inline lambda function. However, if you were dependent on the old behavior, this change may adversely affect the outcome of your code especially when your function object stores data members that are expected to be altered by the walk() methods.


trie_map / packed_trie_map

  • The find() method now returns a const_iterator instance rather than a value type. It returns an end position iterator when the method fails to find a match.

  • The prefix_search() method now returns a search_results instance that has begin() and end() methods to allow iterating through the result set.

  • The constructor no longer takes a null value parameter.

  • Some nested type names have been renamed:

    • string_type -> key_type

    • char_type -> key_unit_type

    • string_buffer_type -> key_buffer_type

  • Some functions expected from the key trait class have been renamed:

    • init_buffer() -> to_key_buffer()

    • to_string() -> to_key()

  • The kay trait class now expects the following additional static methods:

    • key_buffer_type to_key_buffer(const key_type& key)

    • key_unit_type* buffer_data(const key_buffer_type& buf)

    • size_t buffer_size(const key_buffer_type& buf)


  • The search_result nested class has been renamed to search_results, to keep the name consistent with that of the same name in trie_map and packed_trie_map.


  • The matrix trait structure (formerly known as the string trait structure) now needs to specify the type of block that stores integer values as its integer_element_block member.


  • Starting with version 1.0, mdds now requires support for C++11. Stick with 0.12 or earlier versions if you use a compiler that doesn’t support C++11.

  • data_type has been renamed to value_type for segment_tree, rectangle_set, and point_quad_tree.



  • The number of template parameters in custom_block_func1, custom_block_func2 and custom_block_func3 have been reduced by half, by deducing the numerical block type ID from the block type definition directly. If you use the older variant, simply remove the template arguments that are numerical block IDs.



  • The search_tree() method in 0.8.0 returns std::pair<const_iterator, bool> instead of just returning bool as of 0.7.1. If you use this method and relies on the return value of the old version, use the second parameter of the new return value which is equivalent of the previous return value.



  • The search() method now returns ::std::pair<const_iterator, bool>. This method previously returned only bool. Use the second parameter of the new return value which is equivalent of the previous return value.