VS2019开发一个项目，报错：如下，
error LNK2001: unresolved external symbol __imp___CrtDbgReport
error LNK2001: unresolved external symbol __imp___invalid_parameter
error LNK2001: unresolved external symbol __imp___CrtDbgReportW
error LNK2001: unresolved external symbol __imp___CrtDbgReportW
error LNK2001: unresolved external symbol __imp___CrtDbgReportW
error LNK2001: unresolved external symbol __imp___free_dbg
error LNK2001: unresolved external symbol __imp___malloc_dbg
对应的中文版报错如下， 严重性 代码 说明 项目 路径 文件 行 禁止显示状态 错误 LNK2019 无法解析的外部符号 __imp__invalid_parameter， 错误 LNK2019 无法解析的外部符号 __imp__calloc_dbg， 错误 LNK2019 无法解析的外部符号 __imp__CrtDbgReport， 错误 LNK2019 无法解析的外部符号 __imp__free_dbg， 错误 LNK2019 无法解析的外部符号 __imp__malloc_dbg， 错误 LNK1120 5 个无法解析的外部命令
看名称，应该是某个库找不到，但到底是哪个库呢？能过搜索后发现，是ucrtd.lib这个库。
具体可能考：
Visual Studio FeedbackDeveloper community 2
https://developercommunity.visualstudio.com/t/5-unresolved-external-symbols-when-linking-vc-proj/593359其中有一段是这么说的，
The upgraded project is missing a reference to the Universal CRT, specifically ucrtd.lib. This library comes from the Windows 10 SDK and is part of the VS 2015/Windows 10 change which brings portions of the C-runtime into the OS. Details on this change and other potential issues you may find upgrading to VS 2015 and later can be found here:
Microsoft C++ porting and upgrading guide | Microsoft Docs
And the specific page related to the Universal CRT:
Upgrade your code to the Universal CRT | Microsoft Docs
From what I can tell, the following changes are needed to the supplied repro projects to resolve the link errors:
- Add $(UniversalCRT_LibraryPath_x86) to Linker->General->“Additional Library Directories”
- Add ucrtd.lib to Linker->Input->“Additional Dependencies”
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