Global Functions

This is a discussion on Global Functions within the C Programming forums, part of the General Programming Boards category; Hi, I am getting a compiler error: [Linker error] undefined reference to 'send_packet' I get this error when I try ...

  1. #1
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    Apr 2009
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    Global Functions

    Hi,

    I am getting a compiler error:

    [Linker error] undefined reference to 'send_packet'
    I get this error when I try to compile example-635.c

    example-635.c
    Code:
    int main(int argc, char* argv[])
      {
      printf("Ultra-simple CFA-635 command-line communications example.\n");
      printf("Crystalfontz America, Inc. http://www.crystalfontz.com\n\n");
      printf("Usage:\n");
      printf("%s PORT BAUD\n");
      printf("PORT is COM1\n");
      printf("BAUD is 115200\n");
    
      /*//If only 0 or 1 parameter is entered, prompt for the missing parameter(s)
      if(argc < 3)
        {
          printf("\nMISSING A PARAMETER. Enter both PORT and BAUD.\n\n");
          return(0);
        }*/
    
      //Check for optional "clear" parameter and set flag if found
      /*int
        cleardisplay=0;
      if((argc > 3)&&(!strcmp(argv[3],"clear"))) cleardisplay=1;*/
    
    
    /*  int
        baud;
      //default the baud to 115200
      if(strcmp(argv[2],"19200"))
        baud=115200;
      else
        baud=19200;*/
    
      if(SetupCommPort())
        {
        printf("Could not open port.");
        return(1);
        }
      else
        printf("Comm Port Opened");
    
      //For some reason, Linux seems to buffer up data from the LCD, and they are sometimes
      //dumped at the start of the program. Clear the serial buffer.
      //while(BytesAvail())
      //  GetByte();
    
    //Outgoing command packets. Either clear the screen
    //or send our line information
    //**********************************************
    /*  if(cleardisplay)
      {
        outgoing_response.command = 6;
        outgoing_response.data_length = 0;
        send_packet();
      }
      else
      {*/
        //Send line 1 to the 635 using command 31
        outgoing_response.command = 31;
        outgoing_response.data[0]=0; //col
        outgoing_response.data[1]=0; //row
        memcpy(&outgoing_response.data[2],">>>This is line 1<<<",20);
        outgoing_response.data_length = 22;  //the col & row position + the 20 char data length
        send_packet();
    
    		//CFA-635 communications protocol only allows
    		//one outstanding packet at a time. Wait for the response
    		//packet from the CFA-635 before sending another
    		//packet.
    		int
    		k;
    		int
    		timed_out;
    		timed_out = 1; //default timed_out is true
    		for(k=0;k<=10000;k++)
    		if(check_for_packet())
    			{
    			ShowReceivedPacket();
    			timed_out = 0; //set timed_out to false
    			break;
    			}
    		if(timed_out)
    		printf("Timed out waiting for a response.\n");
    
        //Send line 2 to the 635 using command 31
        outgoing_response.command = 31;
        outgoing_response.data[0]=0; //col
        outgoing_response.data[1]=1; //row
        memcpy(&outgoing_response.data[2],">>>This is line 2<<<",20);
        outgoing_response.data_length = 22;
        send_packet();
    
    		timed_out = 1; //default timed_out is true
    		for(k=0;k<=10000;k++)
    			if(check_for_packet())
    				{
    				ShowReceivedPacket();
    				timed_out = 0; //set timed_out to false
    				break;
    				}
    		if(timed_out)
    			printf("Timed out waiting for a response.\n");
    
        //Send line 3 to the 635 using command 31
        outgoing_response.command = 31;
        outgoing_response.data[0]=0; //col
        outgoing_response.data[1]=2; //row
        memcpy(&outgoing_response.data[2],">>>This is line 3<<<",20);
        outgoing_response.data_length = 22;
        send_packet();
    
    		timed_out = 1; //default timed_out is true
    		for(k=0;k<=10000;k++)
    			if(check_for_packet())
    				{
    				ShowReceivedPacket();
    				timed_out = 0; //set timed_out to false
    				break;
    				}
    		if(timed_out)
    			printf("Timed out waiting for a response.\n");
    
        //Send line 4 to the 635 using command 31
        outgoing_response.command = 31;
        outgoing_response.data[0]=0; //col
        outgoing_response.data[1]=3; //row
        memcpy(&outgoing_response.data[2],">>>This is line 4<<<",20);
        outgoing_response.data_length = 22;
        void send_packet(void);
    
    		timed_out = 1; //default timed_out is true
    		for(k=0;k<=10000;k++)
    			if(check_for_packet())
    				{
    				ShowReceivedPacket();
    				timed_out = 0; //set timed_out to false
    				break;
    				}
    		if(timed_out)
    			printf("Timed out waiting for a response.\n");
      //}
    //**********************************************
    
      printf("\nCtrl-C to exit.\n");
      printf("Updated display, now waiting for packets\n\n");
    
    /*  while(!cleardisplay)
       {
         usleep(100000);  // 1/10 second
         if(check_for_packet())
           ShowReceivedPacket();
       }*/
    
    /*  if(cleardisplay) printf("Display Cleared.\n");
      printf("Done.\n\n");*/
      BreakDownCommPort();
      //Uninit_Serial();
      return 0;
      }
    //============================================================================
    HANDLE SetupCommPort()
    {       
        //
        // get tty settings from settings dialog
        //
        UpdateTTYInfo();
    
        //
        // open communication port handle
        //
        COMDEV( TTYInfo ) = CreateFile( gszPort,  
                                          GENERIC_READ | GENERIC_WRITE, 
                                          0, 
                                          0, 
                                          OPEN_EXISTING,
                                          FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,
                                          0);
    
        if (COMDEV(TTYInfo) == INVALID_HANDLE_VALUE) {   
            ErrorReporter("CreateFile");
            return NULL;
        }
    
        //
        // Save original comm timeouts and set new ones
        //
        if (!GetCommTimeouts( COMDEV(TTYInfo), &(TIMEOUTSORIG(TTYInfo))))
            ErrorReporter("GetCommTimeouts");
    
        //
        // Set port state
        //
        UpdateConnection();
    
        //
        // set comm buffer sizes
        //
        SetupComm(COMDEV(TTYInfo), MAX_READ_BUFFER, MAX_WRITE_BUFFER);
    
        //
        // raise DTR
        //
        if (!EscapeCommFunction(COMDEV(TTYInfo), SETDTR))
            ErrorReporter("EscapeCommFunction (SETDTR)");
    
        //
        // start threads and set initial thread state to not done
        //
        StartThreads();
    
        //
        // set overall connect flag
        //
        CONNECTED( TTYInfo ) = TRUE ;
    
        return COMDEV(TTYInfo);
    }
    'send_packet' is defined in file 'cf_packet.h'

    cf_packet.h
    Code:
    #define MAX_DATA_LENGTH 22
    //============================================================================
    #define MAX_COMMAND 35
    //============================================================================
    typedef struct
      {
      ubyte
        command;
      ubyte
        data_length;
      ubyte
        data[MAX_DATA_LENGTH];
      WORD_UNION
        CRC;
      }COMMAND_PACKET;
    //============================================================================
    word get_crc(ubyte *bufptr,word len,word seed);
    //============================================================================
    extern COMMAND_PACKET
      incoming_command;
    extern COMMAND_PACKET
      outgoing_response;
    //============================================================================
    ubyte check_for_packet(void);
    void send_packet(void);
    //============================================================================
    and send_packet() is declared in file cf_packet.c

    cf_packet.c
    Code:
    #include <stdio.h>
    #include <unistd.h>
    #include "typedefs.h"
    #include "serial.h"
    #include "cf_packet.h"
    //------------------------------------------------------------------------------
    word get_crc(ubyte *bufptr,word len,word seed)
      {
      //CRC lookup table to avoid bit-shifting loops.
      static const word crcLookupTable[256] =
        {0x00000,0x01189,0x02312,0x0329B,0x04624,0x057AD,0x06536,0x074BF,
         0x08C48,0x09DC1,0x0AF5A,0x0BED3,0x0CA6C,0x0DBE5,0x0E97E,0x0F8F7,
         0x01081,0x00108,0x03393,0x0221A,0x056A5,0x0472C,0x075B7,0x0643E,
         0x09CC9,0x08D40,0x0BFDB,0x0AE52,0x0DAED,0x0CB64,0x0F9FF,0x0E876,
         0x02102,0x0308B,0x00210,0x01399,0x06726,0x076AF,0x04434,0x055BD,
         0x0AD4A,0x0BCC3,0x08E58,0x09FD1,0x0EB6E,0x0FAE7,0x0C87C,0x0D9F5,
         0x03183,0x0200A,0x01291,0x00318,0x077A7,0x0662E,0x054B5,0x0453C,
         0x0BDCB,0x0AC42,0x09ED9,0x08F50,0x0FBEF,0x0EA66,0x0D8FD,0x0C974,
         0x04204,0x0538D,0x06116,0x0709F,0x00420,0x015A9,0x02732,0x036BB,
         0x0CE4C,0x0DFC5,0x0ED5E,0x0FCD7,0x08868,0x099E1,0x0AB7A,0x0BAF3,
         0x05285,0x0430C,0x07197,0x0601E,0x014A1,0x00528,0x037B3,0x0263A,
         0x0DECD,0x0CF44,0x0FDDF,0x0EC56,0x098E9,0x08960,0x0BBFB,0x0AA72,
         0x06306,0x0728F,0x04014,0x0519D,0x02522,0x034AB,0x00630,0x017B9,
         0x0EF4E,0x0FEC7,0x0CC5C,0x0DDD5,0x0A96A,0x0B8E3,0x08A78,0x09BF1,
         0x07387,0x0620E,0x05095,0x0411C,0x035A3,0x0242A,0x016B1,0x00738,
         0x0FFCF,0x0EE46,0x0DCDD,0x0CD54,0x0B9EB,0x0A862,0x09AF9,0x08B70,
         0x08408,0x09581,0x0A71A,0x0B693,0x0C22C,0x0D3A5,0x0E13E,0x0F0B7,
         0x00840,0x019C9,0x02B52,0x03ADB,0x04E64,0x05FED,0x06D76,0x07CFF,
         0x09489,0x08500,0x0B79B,0x0A612,0x0D2AD,0x0C324,0x0F1BF,0x0E036,
         0x018C1,0x00948,0x03BD3,0x02A5A,0x05EE5,0x04F6C,0x07DF7,0x06C7E,
         0x0A50A,0x0B483,0x08618,0x09791,0x0E32E,0x0F2A7,0x0C03C,0x0D1B5,
         0x02942,0x038CB,0x00A50,0x01BD9,0x06F66,0x07EEF,0x04C74,0x05DFD,
         0x0B58B,0x0A402,0x09699,0x08710,0x0F3AF,0x0E226,0x0D0BD,0x0C134,
         0x039C3,0x0284A,0x01AD1,0x00B58,0x07FE7,0x06E6E,0x05CF5,0x04D7C,
         0x0C60C,0x0D785,0x0E51E,0x0F497,0x08028,0x091A1,0x0A33A,0x0B2B3,
         0x04A44,0x05BCD,0x06956,0x078DF,0x00C60,0x01DE9,0x02F72,0x03EFB,
         0x0D68D,0x0C704,0x0F59F,0x0E416,0x090A9,0x08120,0x0B3BB,0x0A232,
         0x05AC5,0x04B4C,0x079D7,0x0685E,0x01CE1,0x00D68,0x03FF3,0x02E7A,
         0x0E70E,0x0F687,0x0C41C,0x0D595,0x0A12A,0x0B0A3,0x08238,0x093B1,
         0x06B46,0x07ACF,0x04854,0x059DD,0x02D62,0x03CEB,0x00E70,0x01FF9,
         0x0F78F,0x0E606,0x0D49D,0x0C514,0x0B1AB,0x0A022,0x092B9,0x08330,
         0x07BC7,0x06A4E,0x058D5,0x0495C,0x03DE3,0x02C6A,0x01EF1,0x00F78};
    
      //Initial CRC value is 0x0FFFF.
      register word
        newCrc;
      newCrc=seed;
      //This algorithim is based on the IrDA LAP example.
      while(len--)
        newCrc = (newCrc >> 8) ^ crcLookupTable[(newCrc ^ *bufptr++) & 0xff];
      //Make this crc match the one's complement that is sent in the packet.
      return(~newCrc);
      }
    //============================================================================
    COMMAND_PACKET
      incoming_command;
    COMMAND_PACKET
      outgoing_response;
    //============================================================================
    //                              send_packet()
    //
    // send_packet() will send set the CRC in outgoing_response and send it to
    // the host.
    //----------------------------------------------------------------------------
    void send_packet(void)
      {
      //In order to send the entire packet in one call to "write()", we
      //need to place the CRC packed against the data. If data_length
      //happens to be MAX_DATA_LENGTH, then the position of the CRC is
      //outgoing_response.CRC (like you would expect), but if data_length
      //is less, the CRC moves into the data area, packed into the first
      //unused data position.
      //
      //Create a pointer to the first unused data positions.
      word
       *packed_CRC_position;
      packed_CRC_position=
        (word *)&outgoing_response.data[outgoing_response.data_length];
      *packed_CRC_position=
        get_crc((ubyte *)&outgoing_response,outgoing_response.data_length+2,0xFFFF);
      //command, length, data[data_length], crc, crc
      SendData((ubyte *)&outgoing_response,outgoing_response.data_length+4);
      }
    //============================================================================
    //                              check_for_packet()
    //
    // check_for_packet() will see if there is a valid packet in the input buffer.
    // If there is, it will copy it into incoming_command and return 1. If there
    // is not it will return 0. incoming_packet may get partially filled with
    // garbage if there is not a valid packet available.
    //----------------------------------------------------------------------------
    ubyte check_for_packet(void)
      {
      Sync_Read_Buffer();
      ubyte
        i;
      //First off, there must be at least 4 bytes available in the input stream
      //for there to be a valid command in it (command, length, no data, CRC).
      if((i=BytesAvail())<4)
        return(0);
      //The "peek" stuff allows us to look into the RS-232 buffer without
      //removing the data.
      Sync_Peek_Pointer();
      //Only commands 0 through MAX_COMMAND are valid.
      if(MAX_COMMAND<(0x3F&(incoming_command.command=PeekByte())))
        {
        //Throw out one byte of garbage. Next pass through should re-sync.
        GetByte();
        return(0);
        }
      //There is a valid command byte. Get the data_length. The data length
      //must be within reason.
      if(MAX_DATA_LENGTH<(incoming_command.data_length=PeekByte()))
        {
        //Throw out one byte of garbage. Next pass through should re-sync.
        GetByte();
        return(0);
        }
      //Now there must be at least incoming_command.data_length+sizeof(CRC) bytes
      //still available for us to continue.
      if((int)PeekBytesAvail()<(incoming_command.data_length+2))
        //It looked like a valid start of a packet, but it does not look
        //like the complete packet has been received yet.
        return(0);
      //There is enough data to make a packet. Transfer over the data.
      for(i=0;i<incoming_command.data_length;i++)
        incoming_command.data[i]=PeekByte();
      //Now move over the CRC.
      incoming_command.CRC.as_bytes[0]=PeekByte();
      incoming_command.CRC.as_bytes[1]=PeekByte();
      //Now check the CRC.
      if(incoming_command.CRC.as_word==
         get_crc((ubyte *)&incoming_command,incoming_command.data_length+2,0xFFFF))
        {
        //This is a good packet. I'll be horn swaggled. Remove the packet
        //from the serial buffer.
        AcceptPeekedData();
        //Let our caller know that incoming_command has good stuff in it.
        return(1);
        }
      //The CRC did not match. Toss out one byte of garbage. Next pass through
      //should re-sync.
      GetByte();
      return(0);
      }
    Does anyone know what I need to do to get rid of the [Linker error]? and so I can use send_packet() in example-635.c?

    Any help would be gratly appreciated.

  2. #2
    Registered User
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    cf_packet.c must be compiled and linked with your main program.

  3. #3
    Registered User
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    Thanks Xmariux,

    but how would I compile multiple files?

    Is it:

    gcc -c example-635.c cf_packet.c

    gcc -o example-635.o cfpacket.o example-635

  4. #4
    Registered User
    Join Date
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    2 ways:

    compile main program and linking wiht one command, all objects will be created and an executable will be created after all
    1) gcc -o myprogram example-635.c cf_packet.c


    comlile every source file and then link all objects and compile main
    2)complile cf_packet.c
    gcc -c -o cf_packet.o cf_packet.c

    and compile main program and linked with the object cf_packet.o

    gcc -o myprogram example-635.c cf_packet.o


    wiht -c you compile but the compiler will not try to make an executable just compilation
    you can compile with -c your main program and then u can put all objects just for linking(the third way)
    Last edited by xmariux; 04-15-2009 at 07:33 AM.

  5. #5
    Registered User
    Join Date
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    37
    Hi,

    I have another very similar question:

    Compile error: (.text+0x7):serial.c: undefined reference to 'UpdateTTYInfo'

    This error shows when I run the compile command:
    gcc -o myprogram example-635.c cf_packet.c serial.c show_packet.c SETTINGS.C

    The function UpdateTTYInfo() is defined in file 'SETTINGS.C'

    Code:
    void UpdateTTYInfo() {
     //some code
    }
    The 'UpdateTTYInfo()' function is called in file 'serial.c' that is what gives the compile error.

    To resolve this i created a file called 'settings.h' which iincluded the code

    Code:
    void UpdateTTYInfo(void);
    and #include(d) "settings.h in file 'serial.c' , but still no luck

    Any ideas?

  6. #6
    CSharpener vart's Avatar
    Join Date
    Oct 2006
    Location
    Rishon LeZion, Israel
    Posts
    6,484
    your lines shown in the post are copied from the corresponding files as is?

    first thing I would check - you made no mistakes in the function name in one of the 3 places it is mentioned
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  7. #7
    Registered User
    Join Date
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    20
    change

    Code:
    void UpdateTTYInfo() {
     //some code
    }
    to:

    Code:
    void UpdateTTYInfo(void) {
     //some code
    }
    maybe this is the error , if after this u have errors change SETTINGS.C to SETTINGS.c
    The last change is stupid but i would try it to be sure.

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