Compilation errors with version 3.12 and GCC 13.3 -std=c++20

[agoff7]

I am getting a bunch of errors (67) similar to this:
json-develop/single_include/nlohmann/json.hpp:5821:11: error: 'class nlohmann::json_abi_v3_12_0::basic_json<>' has no member named 'm_data'
5821 | j.m_data.m_value.destroy(j.m_data.m_type);

Has anybody else had this issue or solved it? I obtained the code from a zip download, not GIT. Using this with an embedded application, not Windows or Linux.

[agoff7]

I would be willing to pay for consultation to resolve this issue.

[nlohmann]

Can you share more information? Do you use CMake? if so, how do you invoke it?

[agoff7]

We are building an embedded application that will run on a Xilinx Versal using the ARM R5 processor., Xilinx Vitis is the development environment; it is an Eclipse based GUI. It does use CMake, it is invoked from the build button in Vitis. OS: FreeRTOS Compiler is GNU 13.3 I am using your json library because it is a dependency for the jsonrpc library jsonrpcx/json-rpc-cxx: JSON-RPC for modern C++<https://github.com/jsonrpcx/json-rpc-cxx> I built a prototype application with Visual Studio and it worked just fine, just had to add the include directory for both libraries to the header search path. I repeated the same steps with Vitis, but I am getting those compile errors.

[agoff7]

Are you available to discuss offline?

[nlohmann]

You you reproduce the error with a small example?

[agoff7]

I can reproduce the problem, not with a small example though. It looks like the include order matters. If I include the json library first, I can build and run OK. If the json include file is after some other files it will have the compile errors. I am content with re-ordering the include files to make it work. Thanks for looking at this. From: Niels Lohmann ***@***.***> Sent: Thursday, July 31, 2025 11:19 AM To: nlohmann/json ***@***.***> Cc: Goff, Aaron ***@***.***>; Author ***@***.***> Subject: [EXTERNAL] Re: [nlohmann/json] Compilation errors with version 3.12 and GCC 13.3 -std=c++20 (Discussion #4868) You you reproduce the error with a small example? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread. Message ID: <nlohmann/json/repo-discussions/4868/comments/13950722@ github. com> You you reproduce the error with a small example? — Reply to this email directly, view it on GitHub<https://urldefense.us/v3/__https:/github.com/nlohmann/json/discussions/4868*discussioncomment-13950722__;Iw!!C5Asm8uRnZQmlRln!bR3qKyX8hojqDDcQ0GT_nBnb-2pdgqqxuiHq1RPTozoskHuIT-Uu6owFWMz4MFBkPG2EzWS_FYYcgvCIPndbaUTr4g$>, or unsubscribe<https://urldefense.us/v3/__https:/github.com/notifications/unsubscribe-auth/AKD4B2PEB3HUBKRPJNUKDVL3LJMZZAVCNFSM6AAAAACCSCZRWKVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGOJVGA3TEMQ__;!!C5Asm8uRnZQmlRln!bR3qKyX8hojqDDcQ0GT_nBnb-2pdgqqxuiHq1RPTozoskHuIT-Uu6owFWMz4MFBkPG2EzWS_FYYcgvCIPndhu24qOg$>. You are receiving this because you authored the thread.Message ID: ***@***.******@***.***>>

[nlohmann]

The library should clean up any unrelated symbols. Which headers break the build?

[agoff7]

Lightweight IP stack: #include "lwip/sockets.h" From: Niels Lohmann ***@***.***> Sent: Thursday, July 31, 2025 1:37 PM To: nlohmann/json ***@***.***> Cc: Goff, Aaron ***@***.***>; Author ***@***.***> Subject: [EXTERNAL] Re: [nlohmann/json] Compilation errors with version 3.12 and GCC 13.3 -std=c++20 (Discussion #4868) The library should clean up any unrelated symbols. Which headers break the build? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread. Message ID: <nlohmann/json/repo-discussions/4868/comments/13951808@ github. com> The library should clean up any unrelated symbols. Which headers break the build? — Reply to this email directly, view it on GitHub<https://urldefense.us/v3/__https:/github.com/nlohmann/json/discussions/4868*discussioncomment-13951808__;Iw!!C5Asm8uRnZQmlRln!eDpSwL31m0mVs_WEd7roKCuPot8_qMa3KS9k2qv6C23yQeMxT6RwoLmVaqytPQADd-NU_p4pJ7bn0MgcH6VblGBX_g$>, or unsubscribe<https://urldefense.us/v3/__https:/github.com/notifications/unsubscribe-auth/AKD4B2P5L2WDAZM3LCXVILD3LJ45TAVCNFSM6AAAAACCSCZRWKVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGOJVGE4DAOA__;!!C5Asm8uRnZQmlRln!eDpSwL31m0mVs_WEd7roKCuPot8_qMa3KS9k2qv6C23yQeMxT6RwoLmVaqytPQADd-NU_p4pJ7bn0MgcH6W-H2BY_Q$>. You are receiving this because you authored the thread.Message ID: ***@***.******@***.***>>