| 错误常量 | 字串信息 | 数字代号 | 中文信息 www.51-n.com |
| CURLE_OK | No error | 0 | 没有出现错误 |
| CURLE_UNSUPPORTED_PROTOCOL | Unsupported protocol | 1 | 请求了不受支持的协议 |
| CURLE_FAILED_INIT | Failed initialization | 2 | cURL初始化失败 |
| CURLE_URL_MALFORMAT | URL using bad/illegal format or missing URL | 3 | 网址链接格式不正确或者提供的链接为空，另外注意请求链接必须是绝对链接，不能是相对链接。 |
| CURLE_COULDNT_RESOLVE_PROXY | Couldn't resolve proxy name | 5 | 无法解析代理服务器 |
| CURLE_COULDNT_RESOLVE_HOST | Couldn't resolve host name | 6 | 无法解析主机 |
| CURLE_COULDNT_CONNECT | Couldn't connect to server | 7 | 无法连接远程服务器 |
| CURLE_FTP_WEIRD_SERVER_REPLY | FTP: weird server reply | 8 | 服务器返回无法识别的响应 |
| CURLE_FTP_WEIRD_PASS_REPLY | FTP: unknown PASS reply | 11 | 发送密码后服务器返回无法识别的响应 |
| CURLE_FTP_WEIRD_PASV_REPLY | FTP: unknown PASV reply | 13 | 服务器对PASV命令返回无法识别的响应 |
| CURLE_FTP_WEIRD_227_FORMAT | FTP: unknown 227 response format | 14 | 服务器对 227行为返回无法识别的响应 |
| CURLE_FTP_CANT_GET_HOST | FTP: can't figure out the host in the PASV response | 15 | 找不到主机 |
| CURLE_PARTIAL_FILE | Transferred a partial file | 18 | 文件传输不完整 |
| CURLE_FTP_COULDNT_RETR_FILE | FTP: couldn't retrieve (RETR failed) the specified file | 19 | RETR命令收到了不正常的回复，或完成的传输尺寸为零字节。 |
| CURLE_HTTP_RETURNED_ERROR | HTTP response code said error | 22 | 服务器返回请求错误 等效于CURLE_HTTP_NOT_FOUND |
| CURLE_WRITE_ERROR | Failed writing received data to disk/application | 23 | 无法写入文件 |
| CURLE_FTP_COULDNT_STOR_FILE | Upload failed (at start/before it took off) | 25 | 上传失败 |
| CURLE_READ_ERROR | Failed to open/read local data from file/application | 26 | 无法读取文件 |
| CURLE_OUT_OF_MEMORY | Out of memory | 27 | 内存溢出 |
| CURLE_OPERATION_TIMEDOUT | Timeout was reached | 28 | 超时 |
| CURLE_FTP_PORT_FAILED | FTP: command PORT failed | 30 | 无法响应PORT命令 |
| CURLE_FTP_COULDNT_USE_REST | FTP: command REST failed | 31 | 无法响应REST命令 |
| CURLE_HTTP_POST_ERROR | Internal problem setting up the POST | 34 | POST请求错误 |
| CURLE_SSL_CONNECT_ERROR | SSL connect error | 35 | SSL连接错误 |
| CURLE_FTP_BAD_DOWNLOAD_RESUME | Couldn't resume download | 36 | 无法恢复下载 |
| CURLE_FILE_COULDNT_READ_FILE | Couldn't read a file:// file | 37 | 无法打开FILE://路径下的文件 |
| CURLE_LDAP_CANNOT_BIND | LDAP: cannot bind | 38 | 无法绑定LDAP |
| CURLE_LDAP_SEARCH_FAILED | LDAP: search failed | 39 | LDAP搜索无法进行。 |
| CURLE_FUNCTION_NOT_FOUND | A required function in the library was not found | 41 | 找不到必须的zlib函数 |
| CURLE_ABORTED_BY_CALLBACK | Operation was aborted by an application callback | 42 | 已由回调函数中止 |
| CURLE_BAD_FUNCTION_ARGUMENT | A libcurl function was given a bad argument | 43 | 函数参数错误 |
| CURLE_HTTP_PORT_FAILED | Failed binding local connection end | 45 | 端口错误 |
| CURLE_TOO_MANY_REDIRECTS | Number of redirects hit maximum amount | 47 | 重定向次数过多 |
| CURLE_UNKNOWN_TELNET_OPTION | An unknown option was passed in to libcurl | 48 | 无法识别的选项 |
| CURLE_TELNET_OPTION_SYNTAX | Malformed telnet option | 49 | TELNET格式错误 |
| CURLE_GOT_NOTHING | Server returned nothing (no headers, no data) | 52 | 服务器未返回任何数据 |
| CURLE_SSL_ENGINE_NOTFOUND | SSL crypto engine not found | 53 | 找不到指定的加密引擎。 |
| CURLE_SSL_ENGINE_SETFAILED | Can not set SSL crypto engine as default | 54 | 无法将选定的SSL加密引擎设为默认选项。 |
| CURLE_SEND_ERROR | Failed sending data to the peer | 55 | 无法发送网络数据。 |
| CURLE_RECV_ERROR | Failure when receiving data from the peer | 56 | 无法接收网络数据 |
| CURLE_SSL_CERTPROBLEM | Problem with the local SSL certificate | 58 | 本地客户端证书有问题 |
| CURLE_SSL_CIPHER | Couldn't use specified SSL cipher | 59 | 无法使用指定的密钥 |
| CURLE_SSL_CACERT | Peer certificate cannot be authenticated with given CA certificates | 60 | 无法使用已知的CA证书验证对等证书 |
| CURLE_BAD_CONTENT_ENCODING | Unrecognized or bad HTTP Content or Transfer-Encoding | 61 | 无法识别传输编码 |
| CURLE_LDAP_INVALID_URL | Invalid LDAP URL | 62 | 无效的LDAP网址 |
| CURLE_FILESIZE_EXCEEDED | Maximum file size exceeded | 63 | 文件大小超过上限 |
| CURLE_SSH | Error in the SSH layer | 79 | SSH错误 |
