Thread: 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.

cf_packet.c must be compiled and linked with your main program.

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

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?

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.