最新版open62541 V1.5.4编译生成的open62541.dll,使用 implib -a open62541.lib open62541.dll 可以给C++ Builder 13使用,如果不用open62541.lib,直接使用open62541.c会报一堆的Error: Unresolved externalreferenced from,如图:

根本原因是open62541对c++ Builder的支持不够,主要在open62541.h 259行,C++Builder clang-enhanced 编译open62541.c, 编译命令是C99,不是C11,对static __thread处理不到位,需修改如下:
#if defined(CODEGEARC) defined(BORLANDC)
undef UA_STATIC_THREAD_LOCAL
define UA_STATIC_THREAD_LOCAL /*c++Builder Win32 cannot link function-local static __thread arrays */
#endif