VSCode+MinGW64环境下C++调用预编译OpenSSL出现链接错误求助

问题场景 #

已正确配置OpenSSL头文件路径，但编译C++代码时触发链接错误：

C:/Users/felix/my_future/PMS_Blockchain_CPP/pms_blockchain/src/Wallet.cpp:77: undefined reference to `EVP_PKEY_CTX_new_id'
collect2.exe: error: ld returned 1 exit status

使用环境为VS Code + MinGW64，当前tasks.json配置如下：

{
"tasks": [
  {
    "type": "cppbuild",
    "label": "C/C++: g++.exe build active file",
    "command": "C:\\msys64\\mingw64\\bin\\g++.exe",
    "args": [
      "-fdiagnostics-color=always",
      "-g",
      "${workspaceFolder}\\pms_blockchain\\src\\**.cpp",
      "${workspaceFolder}\\openssl\\**.h",
      "-o",
      "${workspaceFolder}\\${fileBasenameNoExtension}.exe"
    ],
    "options": {
      "cwd": "${fileDirname}"
    },
    "problemMatcher": ["$gcc"],
    "group": {
      "kind": "build",
      "isDefault": true
    },
    "detail": "Task generated by Debugger."
  }
],
"version": "2.0.0"
}

修复步骤 #

链接错误是因为编译时未关联OpenSSL的库文件，需修改tasks.json的编译参数：

1. 移除无效参数：删除${workspaceFolder}\\openssl\\**.h，头文件无需作为编译输入，编译器会通过配置的头文件路径自动查找。
2. 添加库链接参数：在args数组中加入OpenSSL核心库的链接指令，若库文件不在系统默认路径，需先通过-L指定库目录。

修改后的tasks.json #

{
"tasks": [
  {
    "type": "cppbuild",
    "label": "C/C++: g++.exe build active file",
    "command": "C:\\msys64\\mingw64\\bin\\g++.exe",
    "args": [
      "-fdiagnostics-color=always",
      "-g",
      "${workspaceFolder}\\pms_blockchain\\src\\**.cpp",
      // 若OpenSSL库不在系统默认路径，取消下面一行注释并替换为实际库目录
      // "-L${workspaceFolder}\\openssl\\lib",
      "-lssl",
      "-lcrypto",
      "-o",
      "${workspaceFolder}\\${fileBasenameNoExtension}.exe"
    ],
    "options": {
      "cwd": "${fileDirname}"
    },
    "problemMatcher": ["$gcc"],
    "group": {
      "kind": "build",
      "isDefault": true
    },
    "detail": "Task generated by Debugger."
  }
],
"version": "2.0.0"
}

参数说明 #

• -L<路径>：指定编译器查找库文件的目录，需替换为你的OpenSSLlib文件夹实际路径（若库已在系统环境变量路径中可省略）。
• -lssl：链接OpenSSL的SSL库。
• -lcrypto：链接OpenSSL的加密算法库。

内容的提问来源于stack exchange，提问作者Felix Jost