如何解决libcurl与TWS API运行时的数据重叠问题

我在C++项目中同时运行libcurl发送邮件与TWS API（连接端口为4002），定期调用libcurl发送邮件时，发现邮件内容混入了TWS API传输的部分数据，目前无法确定导致数据重叠的原因，这是我首次使用libcurl。相关代码如下：

libcurl邮件发送代码 #

string sender = "senderEmail@gmail.com";
string password = "password!";
string receiver1 = "otheremail@gmail.com";
string receiver2 = "5551234567@msg.fi.google.com";

string latestEmailSubject = "default Subject";
string latestEmailBody = "email Body";

size_t writeCallback(void* contents, size_t size, size_t nmemb, void* userp) {
    // Simply discard the response for simplicity in this example
    return size * nmemb;
}
struct upload_status {
    int lines_read;
};
static size_t payload_source(void* ptr, size_t size, size_t nmemb, void* userp)
{
    struct upload_status* upload_ctx = (struct upload_status*)userp;
    const char* data;

    if ((size == 0) || (nmemb == 0) || ((size * nmemb) < 1)) {
        return 0;
    }

    cout << "sending" << endl;

    string senderLine = ("From: " + sender + "\r\n");
    string receiverLine = "To: " + receiver1 + "\r\n";
    string ccLine = "Cc: " + receiver2 + "\r\n";

    string subjectLine = "Subject: " + latestEmailSubject + "\r\n";
    string bodyLine = latestEmailBody + "\r\n";
    string footerLine = "Sent from Accelerated Investing at " + StockThread::TimeToString(system_clock::now()) + "\r\n";

    static const char* payload_text[] = {
  "Date: Mon, 29 Nov 2023 21:54:29 +1100\r\n",
    receiverLine.c_str(),
    senderLine.c_str(),
    ccLine.c_str(),
    "Message-ID: <dcd7cb36-11db-487a-9f3a-e652a9458efd@"
    "rfcpedant.example.org>\r\n",
    subjectLine.c_str(),
    "\r\n", 
    bodyLine.c_str(),
    "\r\n",
    footerLine.c_str(),
    //"Check RFC5322.\r\n",
    NULL
    };

    data = payload_text[upload_ctx->lines_read];

    if (data) {
        size_t len = strlen(data);
        memcpy(ptr, data, len);
        upload_ctx->lines_read++;

        return len;
    }

    cout << "end of payload_source()" << endl;


    return 0;
}


void Strategy::SendEmail(string subject, string message)
{
    CURL* curl = curl_easy_init();
    
    struct upload_status upload_ctx;

    upload_ctx.lines_read = 0;

    if (curl) 
    {
        latestEmailSubject = subject;
        latestEmailBody = message;

        // Set the SMTP server details
        curl_easy_setopt(curl, CURLOPT_URL, "smtps://smtp.gmail.com:465");
        curl_easy_setopt(curl, CURLOPT_USERNAME, "senderEmail@gmail.com");
        
        // generated password copied from gmail
        curl_easy_setopt(curl, CURLOPT_PASSWORD, "1234 5678 90ab cdef");

        // Set the sender's email address
        curl_easy_setopt(curl, CURLOPT_MAIL_FROM, sender);
        // Set the recipient's email address
        struct curl_slist* recipients = NULL;
        recipients = curl_slist_append(recipients, receiver1.c_str());
        recipients = curl_slist_append(recipients, receiver2.c_str());
        curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
        
        // Set the email body
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
        curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
        curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
        // Set the callback function to handle the server response
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeCallback);

        cout << "sending:" << endl;
        cout << "sending subject:" << subject << endl;
        cout << "sending body:" << message << endl;
        // Perform the email sending operation
        CURLcode res = curl_easy_perform(curl);
        // Check for errors
        if (res != CURLE_OK) 
        {
            std::cerr << "curl_easy_perform() failed: " << curl_easy_strerror(res) << std::endl;
        }
        // Cleanup
        curl_slist_free_all(recipients);
        curl_easy_cleanup(curl);

        cout << "end of SendEmail()" << endl;
    }

}

TWS API初始化代码 #

const char* host = argc > 1 ? argv[1] : "";
int port = argc > 2 ? atoi(argv[2]) : 0;
if (port <= 0)
    port = 4002;
string connectOptions = "";
int clientId = 0;

unsigned attempt = 0;

for (;;) {

    Strategy client;
    EClientSocket* socketpointer = client.m_pClient;

    client.runningLiveTest = testOnlineOrders || exportingOnlineData;
       
    if (!client.isConnected())
    {
        client.connect(host, port, clientId);
    }
    …

此外，程序还会将一些字符串存入vector，准备发送至spdlog。

内容的提问来源于stack exchange，提问作者grizzlyborg