[PeterT]

For what it's worth.... this worked for me. Sorry I am NOT a c++ programmer; just found some examples on the web and modified them.

Spoiler:

	STARTUPINFO si;
    PROCESS_INFORMATION pi;

	WCHAR pCalibre[] = L"\"C:\\Program Files (x86)\\Calibre2\\calibre-smtp.exe\" -e SSL -r smtp.qq.com -u myuserid -p mypassword --port 465 -v -s \"Email_title\" xx@qq.com yy@foxmail.com \"mailBody\"";

    ZeroMemory( &si, sizeof(si) );
    si.cb = sizeof(si);
    ZeroMemory( &pi, sizeof(pi) );

//    if( argc != 2 )
//    {
//        printf("Usage: %s [cmdline]\n", argv[0]);
//        return -1;
//    }

    // Start the child process. 
    if( !CreateProcess( NULL,   // No module name (use command line)
        pCalibre,       // Command line
        NULL,           // Process handle not inheritable
        NULL,           // Thread handle not inheritable
        FALSE,          // Set handle inheritance to FALSE
        0,              // No creation flags
        NULL,           // Use parent's environment block
        NULL,           // Use parent's starting directory 
        &si,            // Pointer to STARTUPINFO structure
        &pi )           // Pointer to PROCESS_INFORMATION structure
    ) 
    {
        printf( "CreateProcess failed (%d).\n", GetLastError() );
        return -1;
    }

    // Wait until child process exits.
    WaitForSingleObject( pi.hProcess, INFINITE );

    // Close process and thread handles. 
    CloseHandle( pi.hProcess );
    CloseHandle( pi.hThread );
	
	return 0;