Windows + vcpkg: unresolved external symbol `dpp::bignumber::bn_deleter::operator()` when linking minimal example

[k03440k]

Describe the bug

When building a minimal DPP project on Windows using vcpkg, CMake, and Visual Studio 2022, the linker fails with an unresolved external symbol related to dpp::bignumber::bn_deleter::operator().

This happens even with a trivial example that only constructs a dpp::cluster. Reinstalling DPP and its dependencies does not resolve the issue.

To Reproduce

1. Install vcpkg and integrate it with CMake / Visual Studio.

2. Install DPP via vcpkg:

   vcpkg install dpp:x64-windows

3. Create the following minimal project.

CMakeLists.txt

cmake_minimum_required(VERSION 3.20)
project(DPPTest)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(dpp CONFIG REQUIRED)

add_executable(dpp_test main.cpp)
target_link_libraries(dpp_test PRIVATE dpp::dpp)

main.cpp

#include <dpp/dpp.h>

int main()
{
    dpp::cluster bot("YOUR_TOKEN_HERE");
    return 0;
}

4. Configure and build the project with CMake / Visual Studio 2022.
5. Observe the linker error.

---

Build error

unresolved external symbol
"public: void __cdecl dpp::bignumber::bn_deleter::operator()(
    struct dpp::openssl_bignum *
) const"
(??Rbn_deleter@bignumber@dpp@@QEBAXPEAUopenssl_bignum@2@@Z)

referenced in function
"public: __cdecl std::unique_ptr<
    struct dpp::openssl_bignum,
    struct dpp::bignumber::bn_deleter
>::~unique_ptr(void)"

However, if I put the next files into the folder with CMakeLists.txt and main.cpp, it successfully builds with dpp 10.1.3:

vcpkg.json

{
  "name": "test-dpp",
  "version-string": "0.1.0",
  "dependencies": [
    {
      "name": "dpp",
      "version>=": "10.1.3"
    }
  ]
}

vcpkg-configuration.json

{
  "default-registry": {
    "kind": "git",
    "repository": "https://github.com/microsoft/vcpkg",
    "baseline": "1dfb48f422cb9d17eb0ac5eea087fd3b66a2ba4d"
  }
}

---

System Details

• OS: Windows 10 (x64)
• Compiler / IDE: Visual Studio 2022 (17.14.23)
• Build system: CMake
• Package manager: vcpkg
• DPP version: 10.1.4 (vcpkg)

Installed vcpkg packages(./vcpkg list)

dpp:x64-windows                                   10.1.4              D++ Extremely Lightweight C++ Discord Library.
nlohmann-json:x64-windows                         3.12.0#1            JSON for Modern C++
openssl:x64-windows                               3.6.0#3             OpenSSL is an open source project that provides ...
opus:x64-windows                                  1.5.2#1             Totally open, royalty-free, highly versatile aud...
vcpkg-cmake-config:x64-windows                    2024-05-23
vcpkg-cmake-get-vars:x64-windows                  2025-05-29
vcpkg-cmake:x64-windows                           2024-04-23
zlib:x64-windows                                  1.3.1               A compression library

---

Additional notes

• The error occurs on a clean build.
• Reinstalling DPP and all its dependencies did not help.
• Clearing the build directory and reconfiguring from scratch did not help either.

Any guidance on whether this is a known issue or a missing linkage/configuration step would be greatly appreciated.