Docs Menu
Docs Home
/
Languages
/
C++
/
C++ Driver

What's New

On this page

  • Overview
  • Types of Breaking Changes
  • What's New in 3.10
  • What's New in 3.9

Overview

Learn what's new in:

  • Version 3.10

  • Version 3.9

Types of Breaking Changes

New versions of the C++ driver can introduce the following types of breaking changes:

  • API changes concern the API of the C++ driver libraries. These changes are accompanied by an API major version bump. You might need to edit C++ source code in your project to address these changes.

    Example

    • Removes the declaration of function v1::func(). (The definition is still provided for ABI compatibility.)

    • Removes the inline function v_noabi::func().

    • Removes v_noabi::func().

    • Changes the redeclaration of bsoncxx::foo from v1::foo to v2::foo. To continue using the old interface, qualify bsoncxx::foo as bsoncxx::v1::foo.

  • ABI changes concern the ABI of the C++ driver libraries. These changes are accompanied by an ABI version bump, and may also be accompanied by an API major version bump. You might need to rebuild your project or edit your C++ source code to address these changes.

    ABI stability is not supported for symbols corresponding to entities declared in the v_noabi namespace. Breaking changes for such symbols are not necessarily accompanied by an ABI version bump.

    Example

    • Removes the exported symbol v_noabi::func().

    • Removes the exported symbol v1::func().

    • Removes the exported symbols for v1::type.

  • Build system changes concern the build system or packaging of the C++ driver libraries. These changes are not necessarily accompanied by either an API major version bump or an ABI version bump. To address these changes, you might need to modify your build system configurations or update your project's package or dependency management settings. You might also need to modify or rebuild your C++ source code.

    Example

    • Removes the ENABLE_FOO configuration variable.

    • Changes the default value of the ENABLE_BAR configuration variable from OFF to ON.

    • Drops support for platform A, compiler B, or architecture C.

What's New in 3.10

Warning

Build System Breaking Changes

The v3.10 driver introduces the following breaking changes to the build system:

  • Drops support for calling find_package(libbsoncxx) and find_package(libmongocxx). Use find_package(bsoncxx) and find_package(mongocxx) instead.

  • Drops support for the LIBBSONCXX_* and LIBMONGOCXX_* CMake variables provided by the legacy CMake package config files. Use the mongo::bsoncxx_* and mongo::mongocxx_* CMake targets instead.

  • Removes the BSONCXX_POLY_USE_STD_EXPERIMENTAL CMake option and drops support for selecting the experimental C++ standard library as a polyfill option.

The v3.10.0 driver release includes the following new features:

  • Adds forward headers that provide non-defining declarations of bsoncxx and mongocxx class types. The driver does not support user-defined forward declarations of any library entity. To obtain the declaration or definition of a library entity, always include the corresponding header.

  • The CMake option ENABLE_BSONCXX_USE_POLY_IMPLS allows selecting bsoncxx implementations of C++17 polyfills by default when no polyfill library is requested. This option is OFF by default.

  • The CMake option BSONCXX_POLY_USE_IMPLS allows selecting bsoncxx implementations of C++17 polyfills instead of external libraries or the C++ standard library. This option is OFF by default.

  • The bsoncxx::v_noabi and mongocxx::v_noabi namespaces are no longer declared inline. Root namespace declarations are still supported and expected to remain equivalent to their prior definitions. For example, bsoncxx::document is still equivalent to bsoncxx::v_noabi::document, and mongocxx::client is still equivalent to mongocxx::v_noabi::client.

  • By default, when library filenames are compiled with MSVC (as detected by CMake's MSVC variable), they are embedded with an ABI tag string. These strings are similar to the following:

    bsoncxx-v_noabi-rhs-x64-v142-md.lib

    To disable this behavior, set ENABLE_ABI_TAG_IN_LIBRARY_FILENAMES=OFF as part of your CMake configuration.

    The ABI tag string can also be embedded in pkg-config metadata filenames, similar to the following:

    libbsoncxx-v_noabi-rhs-x64-v142-md.pc

    To enable this behavior, set ENABLE_ABI_TAG_IN_LIBRARY_FILENAMES=ON and ENABLE_ABI_TAG_IN_PKGCONFIG_FILENAMES=ON as part of your CMake configuration.

To learn more about this release, see the v3.10 Release Notes on GitHub.

What's New in 3.9

Warning

Build System Breaking Changes

The v3.9 driver introduces the following breaking changes:

  • Removes support for exported targets from the CMake project build tree

  • Drops support for macOS 10.14, macOS 10.15, and Ubuntu 14.04

  • Requires MongoDB C Driver v1.25.0 or later

  • Requires CMake v3.15 or later to support the FetchContent module

The v3.9 driver release includes the following new features:

  • The C++ driver container image is now available on Docker hub.

  • The driver automatically downloads the MongoDB C Driver dependency if you don't provide it.

  • The driver no longer builds tests as part of the all target. To build tests, set BUILD_TESTING=ON as part of your CMake configuration.

  • The driver uses the FetchContent module to download and build the MNMLSTC Core polyfill library, if not provided by the system, instead of the ExternalProject module. It also does not patch include directives in MNMLSTC Core headers.

  • Adds the CMake option MONGOCXX_OVERRIDE_DEFAULT_INSTALL_PREFIX. If this option is set to TRUE, the CMAKE_INSTALL_PREFIX option defaults to the build directory. The default value of this option is TRUE.

  • Adds an API for managing Atlas Search indexes.

  • Adds the VERSIONINFO resource to bsoncxx.dll and mongocxx.dll.

  • Explicitly documents that throwing an exception from an APM callback is undefined behavior.

  • Does not prematurely install MNMLSTC Core headers during the CMake build step.

  • Requires that a MongoDB C Driver CMake package is found via find_dependency() for all installed C++ driver package configurations.

To learn more about this release, see the v3.9 Release Notes on GitHub.

Back

ABI Versioning