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Thread: CreateFile Failed problem

  1. #16
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    Re: CreateFile Failed problem

    Quote Originally Posted by wklove2003 View Post
    Sorry, I just havent been able to get a GetLastError() function to return anything.
    What do you mean "not return anything?"
    Code:
    if (mFd == INVALID_HANDLE_VALUE)
     {
        DWORD dwError = GetLastError();
        printf("The value of the error code is %d\n", dwError);
    }
    That is all we have been waiting for all this time. What is the error value?

    In general:
    Code:
    if ( ThisFunctionCallReturnedFailure )
    {
        DWORD dwError  = GetLastError( );
        // dwError now has the reason code for why the function failed
    }
    That is what your original code was missing -- you never checked at all for the reason code for the failure. All you did was check for failure, and all we asked you to do is go further and check the reason for the failure by calling GetLastError(). That doesn't sound complex to me.
    I am a complete newb to programming, but unfortunately, have been handed a project that is dealing with a fairly complex program that was downloaded. So most of the code I have posted, I did not actually do. Just trying to get this program to run properly ASAP
    What we asked you to do has nothing to do with the size or complexity of the program.

    All we wanted was you to make a single function call, GetLastError() and see what value is returned, instead of being in the dark as to why CreateFile fails. If you can't do that, then may I suggest you get someone else to finish your program, since what we asked is the simplest of things.

    Regards,

    Paul McKenzie
    Last edited by Paul McKenzie; September 9th, 2010 at 12:26 PM.

  2. #17
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    Arjay is offline Moderator / MS MVP Power Poster
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    Re: CreateFile Failed problem

    Quote Originally Posted by wklove2003 View Post
    Sorry, I just havent been able to get a GetLastError() function to return anything.
    Post the code that you written that shows us the GetLastError( ) calls. You need to call GetLastError immediately after an error occurs in another api call; otherwise it doesn't work. See the CreateFileA example that Victor posted a while ago.

    ...

    Just trying to get this program to run properly ASAP[/QUOTE]The folks replying here are trying to help you. What you need to do is do what they suggest. It's also helpful if you post back code of what you've done rather than trying to describe what you think you did.

    For example, you mentioned that you haven't been able to get GetLastError( ) to return anything. Without seeing the code, we can only guess where you put it or how you called it. If you post the code, we can immediately spot any errors.

  3. #18
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    Re: CreateFile Failed problem

    "The value of the error code is 2"

    That is saying that it cannot find the specified file correct? So I know that should be self explanatory, but can you explain to me what file it is talking about and what to do to correct this?
    Last edited by wklove2003; September 10th, 2010 at 11:21 AM.

  4. #19
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    Re: CreateFile Failed problem

    On a seperate note, I do appreciate you guys for trying to help and I apologize.

  5. #20
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    Re: CreateFile Failed problem

    Quote Originally Posted by wklove2003 View Post
    "The value of the error code is 2"

    That is saying that it cannot find the specified file correct? So I know that should be self explanatory, but can you explain to me what file it is talking about and what to do to correct this?
    Who knows what file it's talking about when you haven't included the code.

    How come you haven't posted the code after being asked several times to do so? Do you actually read the replies?

  6. #21
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    15

    Re: CreateFile Failed problem

    Code:
    bool Serial::connect()
    {
      if (mConnected)
      {
        printf("You are already connected, please disconnect first\n");
        return false;
      }
      
      COMMTIMEOUTS cto;
      DCB dcb;
      char parity, stop_bits;
      int speed;
    	 	 
      if (mFd != INVALID_HANDLE_VALUE && !CloseHandle(mFd)){
        printf("Can't close comm port");
        return false;
      }
     
      mFd = CreateFileA(mDevice,
    		    GENERIC_READ|GENERIC_WRITE,
    		    0,
    		    NULL,
    		    OPEN_EXISTING,
    		    0,
    		    NULL);
    	 
      if(mFd == INVALID_HANDLE_VALUE){
        char port[64];
        strcpy(port, "\\\\.\\");
        strcat(port, mDevice);
        mFd = CreateFileA(port,
    		      GENERIC_READ|GENERIC_WRITE,
    		      0,
    		      NULL,
    		      OPEN_EXISTING,
    		      0,
    		      NULL);
    		 
        if(mFd == INVALID_HANDLE_VALUE){
    	    DWORD dwError = GetLastError();
        printf("The value of the error code is %d\n", dwError);
    	printf("CreateFile Failed \n");
          return false;
        } 
      }
    
      if(!SetupComm(
           mFd,	// handle of communications device
           1024,	// size of input buffer
           1024	// size of output buffer
           )
        ){
        printf("SetupComm failed \n");
        CloseHandle(mFd);
        return false;
      }
    	 
      // verify baudrate and pairty
    	 
      // set DCB
      switch (mBaud) {
      case 110:
        speed = CBR_110;
        break;
      case 300:
        speed = CBR_300;
        break;
      case 600:
        speed = CBR_600;
        break;
      case 1200:
        speed = CBR_1200;
        break;
      case 2400:
        speed = CBR_2400;
        break;
      case 4800:
        speed = CBR_4800;
        break;
      case 9600: 
        speed = CBR_9600;
        break;
      case 19200:
        speed = CBR_19200;
        break;
      case 38400:
        speed = CBR_38400;
        break;
      case 57600:
        speed = CBR_57600;
        break;
      case 115200:
        speed = CBR_115200;
        break;
      default:
        speed = CBR_9600;
        printf("WARNING Unknown baud rate %d for %s (B9600 used)\n",
    	   mBaud, mDevice);
      }
    
      if (strncmp(mParity, "none", 4) == 0) {
        parity = NOPARITY;
      } else if (strncmp(mParity, "even", 4) == 0) {
        parity = EVENPARITY;
      } else {
        /* odd */
        parity = ODDPARITY;
      }
    
      /* Stop bit (1 or 2) */
      if (mStopBit == 1)
        stop_bits = ONESTOPBIT;
      else /* 2 */
        stop_bits = TWOSTOPBITS;
    
      memset(&dcb,0,sizeof(dcb));
      dcb.DCBlength = sizeof(dcb);
      dcb.BaudRate = speed;
      dcb.fBinary = TRUE;
      dcb.StopBits = stop_bits;
      dcb.Parity = parity;
      dcb.ByteSize = mDataBit;
    	 
    
      dcb.fDtrControl = DTR_CONTROL_DISABLE;
      dcb.fOutxCtsFlow = FALSE ;	 
      dcb.fRtsControl = RTS_CONTROL_DISABLE;
    	 
      // setup software flow control
      dcb.fInX = dcb.fOutX = 0;
    		 
      memset(&cto, 0, sizeof(cto));
      cto.ReadIntervalTimeout = 100;
      cto.ReadTotalTimeoutMultiplier = 1;
      cto.ReadTotalTimeoutConstant = 1000;
      cto.WriteTotalTimeoutMultiplier = cto.ReadIntervalTimeout;
      cto.WriteTotalTimeoutConstant = 1000;	 
    
      if(!SetCommTimeouts(mFd, &cto)){
        printf("SetTimeouts failed ");
    	CloseHandle(mFd);
        return false;
      }	 
    	 
      if(!SetCommState(mFd, &dcb)){
        printf("SetCommState failed \n");
    	CloseHandle(mFd);
        return false;
      }
    	 
      mConnected = true;
      
      return true;
    }
    
    bool Serial::disconnect()
    {
      if (mConnected)
      {
        CloseHandle(mFd);
        mConnected = false;
    	mFd = INVALID_HANDLE_VALUE;
        return true;
      }
      else
      {
        return false;
      }
    }
    
    int Serial::read(char *aBuffer, int aLen)
    {
      int ret;
      DWORD bytes_read;
      if(ReadFile(mFd, aBuffer, aLen, &bytes_read, NULL) ) 
      {
        ret = bytes_read;
      }
      else
      {
        DWORD errors;
        COMSTAT status;
        
        ClearCommError(mFd, &errors, &status);
        ret = -1;
      }
    
      return ret;
    }
    
    int Serial::write(const char *aBuffer, int aLen)
    {
      DWORD bytes_written;
      int ret;
      if(WriteFile(mFd, aBuffer, aLen, &bytes_written, NULL) ) 
      {
        ret = bytes_written;
      }
      else
      {
        DWORD errors;
        COMSTAT status;
        ClearCommError(mFd,&errors,&status);
        ret = -1;
      }
      return ret;
    }
    The code you are looking for?

  7. #22
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    Arjay is offline Moderator / MS MVP Power Poster
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    Re: CreateFile Failed problem

    Why not also print out the port along with the error code so you know what path is failing?

    You're also just blindly retrying and don't check the GetLastError value on the first attempt. Maybe your error is something different than with the 2nd attempt?

    Code:
    mFd = CreateFileA(mDevice,
    		    GENERIC_READ|GENERIC_WRITE,
    		    0,
    		    NULL,
    		    OPEN_EXISTING,
    		    0,
    		    NULL);
    	 
    if(mFd == INVALID_HANDLE_VALUE)
    {
        printf("CreateFile on %s failed with error code: %d \n"
          , mDevice
          , GetLastError( ) );
        char port[64];
        strcpy(port, "\\\\.\\");
        strcat(port, mDevice);
        mFd = CreateFileA(port,
    		      GENERIC_READ|GENERIC_WRITE,
    		      0,
    		      NULL,
    		      OPEN_EXISTING,
    		      0,
    		      NULL);
    		 
        if(mFd == INVALID_HANDLE_VALUE)
        {
          printf("CreateFile on %s failed with error code: %d \n"
            , port
            , GetLastError( ) );
    
          printf("CreateFile Failed \n");
          
          return false;
        }
    
      return true;
    }

  8. #23
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    Posts
    15

    Re: CreateFile Failed problem

    Code:
    bool Serial::connect()
    {
      if (mConnected)
      {
        printf("You are already connected, please disconnect first\n");
        return false;
      }
      
      COMMTIMEOUTS cto;
      DCB dcb;
      char parity, stop_bits;
      int speed;
    	 	 
      if (mFd != INVALID_HANDLE_VALUE && !CloseHandle(mFd)){
        printf("Can't close comm port");
        return false;
      }
     
      mFd = CreateFileA(mDevice,
    		    GENERIC_READ|GENERIC_WRITE,
    		    0,
    		    NULL,
    		    OPEN_EXISTING,
    		    0,
    		    NULL);
    	 
      if(mFd == INVALID_HANDLE_VALUE)
      {
        printf("CreateFile on %s failed with error code: %d \n"
          , mDevice
          , GetLastError( ) );
    	  char port[64];
        strcpy(port, "\\\\.\\");
        strcat(port, mDevice);
        mFd = CreateFileA(port,
    		      GENERIC_READ|GENERIC_WRITE,
    		      0,
    		      NULL,
    		      OPEN_EXISTING,
    		      0,
    		      NULL);
    		 
        if(mFd == INVALID_HANDLE_VALUE){
    	    printf("CreateFile on %s failed with error code: %d \n"
            , port
            , GetLastError( ) );
    	printf("CreateFile Failed \n");
          return false;
        } 
      }
    "CreateFile Failed
    CreateFile on C:\Documents an=failed with error code: 2
    CreateFile on \\.\C:\Documents an=failed with error code: 2"

    Why did it not show the full path?
    Last edited by wklove2003; September 10th, 2010 at 12:06 PM.

  9. #24
    Arjay's Avatar
    Arjay is offline Moderator / MS MVP Power Poster
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    Re: CreateFile Failed problem

    Now we're getting somewhere. Isn't it much easier to debug now that you're printing out some debugging info?

    Quote Originally Posted by wklove2003 View Post
    "CreateFile Failed
    CreateFile on C:\Documents an=failed with error code: 2
    CreateFile on \\.\C:\Documents an=failed with error code: 2"

    Why did it not show the full path?
    How large is the mDevice buffer? Is the buffer too small and truncating your string?

    Btw, is there any reason you don't use CString instead of the old fashioned string buffers?

  10. #25
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    15

    Re: CreateFile Failed problem

    Most of this was written by someone else, so I am not sure why they did not use CString.

    Here is the string_buffer.cpp
    Code:
    #include "internal.hpp"
    #include "string_buffer.hpp"
    
    StringBuffer::StringBuffer(const char *aString)
    {
      mLength = mSize = 0;
      mTimestamp[0] = 0;
      if (aString != 0)
      {
        append(aString);
      }
      else
      {
        mBuffer = 0;
      }
    }
    
    StringBuffer::~StringBuffer()
    {
      if (mBuffer != 0)
        free(mBuffer);
    }
    
    const char *StringBuffer::append(const char* aString)
    {
      /* Include additional length for timestamp */
      size_t len = strlen(aString);
      size_t totalLength = mLength + len;
      size_t tsLen = strlen(mTimestamp);
      if (mLength == 0)
        totalLength += tsLen;
      if (totalLength >= mSize)
      {
        size_t newLen = ((totalLength / 1024) + 1) * 1024;
        char *newBuffer = (char*) malloc(newLen);
        memcpy(newBuffer, mBuffer, mLength);
        
        free(mBuffer);
        mBuffer = newBuffer;
        mSize = newLen;
      }
      
      if (mLength == 0 && tsLen > 0)
      {
        strcpy(mBuffer, mTimestamp);
        mLength += tsLen;
      }
    
      strcpy(mBuffer + mLength, aString);
      mLength += len;
      
      return mBuffer;
    }
    
    void StringBuffer::reset()
    {
      if (mBuffer != 0)
      {
        mBuffer[0] = 0;
        mLength = 0;
      }
    }
    
    void StringBuffer::timestamp()
    {
    #ifdef WIN32
      SYSTEMTIME st;
      GetSystemTime(&st);
      sprintf(mTimestamp, "%4d-%02d-%02dT%02d:%02d:%02d.%04d", st.wYear, st.wMonth, st.wDay, st.wHour, st.wMinute, st.wSecond, st.wMilliseconds);
    #else
      struct timeval tv;
      struct timezone tz;
      
      gettimeofday(&tv, &tz);
      
      strftime(mTimestamp, 64, "%Y-%m-%dT%H:%M:%S", gmtime(&tv.tv_sec));
      sprintf(mTimestamp + strlen(mTimestamp), ".%06d", tv.tv_usec);
    #endif
    }
    Associated header String_Buffer.hpp
    Code:
    #ifndef STRING_BUFFER_HPP
    #define STRING_BUFFER_HPP
    
    /*
     * A simple extensible string that can be appended to. The memory will be reused
     * since it maintains its length. The string buffer also supports setting a timestamp
     * that will be prepended to the string once some data is appended.
     *
     * Currently allocating in 1k increments.
     */
    class StringBuffer 
    {
    protected:
      char *mBuffer; /* A resizable character buffer */
      size_t mSize;     /* The allocated size of the string */
      size_t mLength;   /* The length of the string */
      char mTimestamp[64];
      
    public:
      StringBuffer(const char *aString = 0);
      ~StringBuffer();
    
      operator const char *() { return mBuffer; }
      const char *append(const char *aString);
      const char* operator<<(const char *aString) { return append(aString); }
      void reset();
      void timestamp();
      size_t  length() { return mLength; }
    };
    
    #endif
    Any ideas? It seems fine to me, but I honestly do not know.

  11. #26
    Arjay's Avatar
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    Re: CreateFile Failed problem

    Ah, they wrote they're own string class - priceless.

    Check where mDevice has been set. Look at the variable and make sure it isn't truncated. If it is, find out why it gets truncated.

  12. #27
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    Sep 2010
    Posts
    15

    Re: CreateFile Failed problem

    Serial.hpp
    Code:
    #ifndef SERIAL_HPP
    #define SERIAL_HPP
    
    class Serial {
    public:
      class SerialError
      {
      private:
        char mMessage[1024];
    
      public:
        SerialError(const char *aMessage);
        const char *message() const { return mMessage; }
      };
    private:
    
      
    protected:
      /* Descriptor (tty or socket) */
    #ifdef WIN32
      HANDLE mFd;
    #else
      int mFd;
    #endif
      
      /* Flag debug */
      bool mDebug;
      
      /* TCP port */
      int mPort;
      
      /* Device: "/dev/ttyS0", "/dev/ttyUSB0" or "/dev/tty.USA19*"
         on Mac OS X for KeySpan USB<->Serial adapters this string
         had to be made bigger on OS X as the directory+file name
         was bigger than 19 bytes. Making it 67 bytes for now, but
         OS X does support 256 byte file names. May become a problem
         in the future. */
      
    #ifdef __APPLE_CC__
      char mDevice[64];
    #else
      char mDevice[16];
    #endif
      
      /* Bauds: 9600, 19200, 57600, 115200, etc */
      int mBaud;
      
      /* Data bit */
      unsigned char mDataBit;
      
      /* Stop bit */
      unsigned char mStopBit;
      
      /* Parity: "even", "odd", "none" */
      char mParity[5];
      
      /* In error_treat with TCP, do a reconnect or just dump the error */
      bool mErrorHandling;
      
      /* IP address */
      char mIp[16];
      
    #ifndef WIN32
      /* Save old termios settings */
      struct termios mOldTios;
    #endif
    
      bool mConnected;
    
    private:
      int read(char *aBuffer, int len);
      int write(const char *aBuffer, int len);
    
    public:
      Serial(const char *aDevice,
    	 int aBaud, const char *aParity, int aDataBit,
    	 int aStopBit, bool aDebug = false);
      ~Serial();
    
      bool debug() { return mDebug; }
      bool connected() { return mConnected; }
    
      bool connect();
      bool disconnect();
      int  readUntil(const char *aUntil, char *aBuffer, int aLength);
      int  write(char *aBuffer);
      bool flushInput();
    };
    
    #endif
    Serial.cpp
    Code:
    #include "internal.hpp"
    #include "serial.hpp"
    #include <windows.h>
    #include <strsafe.h>
    
    Serial::SerialError::SerialError(const char *aMessage)
    {
      strncpy(mMessage, aMessage, 1023);
      mMessage[1023] = '\0';
    }
    
    Serial::Serial(const char *aDevice,
    	       int aBaud, const char *aParity, int aDataBit,
    	       int aStopBit, bool aDebug)
    {
      mBaud = aBaud;
      strncpy(mDevice, aDevice, sizeof(mDevice) - 1);
      mParity[sizeof(mDevice) - 1] = '\0';
      strncpy(mParity, aParity, sizeof(mParity) - 1);
      mParity[sizeof(mParity) - 1] = '\0';
      mDataBit = aDataBit;
      mStopBit = aStopBit;
      mDebug = aDebug;
    
    #ifdef WIN32
      mFd = INVALID_HANDLE_VALUE;
    #else
      mFd = -1;
    #endif
      mConnected = false;
    }
     
    Serial::~Serial()
    {
      disconnect();
    }
    
    int Serial::readUntil(const char *aUntil, char *aBuffer, int aLength)
    {
      if (!mConnected)
      {
        printf("Trying to read when not connected");
        return -1;
      }
        
      if (mDebug) 
        printf("Reading upto &#37;d bytes or we get a match\n", aLength, aUntil);
    
      int len = 0, count = 0;
      char *cp = aBuffer;
      const char *match = aUntil;
      do
      {
        int ret = read(cp, 1);
        if (ret == -1)
        {
          throw SerialError("Couldn't read");
        }
        if (ret == 0)
        {
          usleep(10 * 1000); // 10 msec
          if (count++ > 100)
          {
    	printf("Read timed out\n");
    	return -1;
          }
        }
        else
        {
          count = 0;
          
          //printf("Received: %d == match: %d\n", *cp, *match); 
          if (*match == *cp)
    	match++;
          else
    	match = aUntil;
    
          // See if we can match the beginnig of the string again.
          if (*match == *cp)
    	match++;
          //printf("Match now: %d\n", *match);
          cp++;
          len++;
        }
      } while (len <= aLength && *match != '\0');
    
      *cp = '\0';
    
      if (mDebug) 
        printf("Read returned: %d - '%s'\n", len, aBuffer);
    
      return len;
    }
    
    int Serial::write(char *aBuffer)
    {
      if (mDebug) 
        printf("Writing '%s'\n", aBuffer);
    
      int ret = write(aBuffer, (int) strlen(aBuffer));
      if (ret < 0)
        throw SerialError("Couldn't write");
      
      if (mDebug) 
        printf("Write returned: %d\n", ret);
      
      return ret;
    }
    
    bool Serial::flushInput()
    {
      char buffer[2];
      int ret;
      do
      {
        ret = read(buffer, 1);
        if (ret < 0)
          throw SerialError("Couldn't read");
      } while (ret > 0);
    
      return true;
    }
    
    #ifdef WIN32
    #include "serial.win32.cpp"
    #else
    #include "serial.unix.cpp"
    #endif
    Is this what you were looking for? Is that setting mDevice, its hard for me to understand it to be honest

  13. #28
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    Posts
    27,418

    Re: CreateFile Failed problem

    What is mDevice declared as? How big is that array? Is it big enough to fit all of these characters? I see it is declared as an array of 64 (or 16) characters. What if there are more characters? What do you do then?

    In general, your code is very faulty, as it does no checking if there is enough room for all of those strings. It is a classic example of how a buffer can be overrun, and therefore exploited by hackers.

    Basically, you have a 'C' program, not a C++ program. Yes, you have some C++ syntax thrown in here and there, but it is basically a 'C' program. It does not use anything of C++ in terms of safety (buffer overruns).

    Regards,

    Paul McKenzie
    Last edited by Paul McKenzie; September 10th, 2010 at 02:23 PM.

  14. #29
    Arjay's Avatar
    Arjay is offline Moderator / MS MVP Power Poster
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    Posts
    10,956

    Re: CreateFile Failed problem

    If you are using a version of Visual C++ that hasn't been written 2 decades ago (i.e. not VC6), just right click on mDevice and choose "Go to declaration".

  15. #30
    Join Date
    Sep 2010
    Posts
    15

    Re: CreateFile Failed problem

    Here is where the declaration is. So 16 characters.
    Code:
    #ifdef __APPLE_CC__
      char mDevice[64];
    #else
      char mDevice[16];
    #endif

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