i2c - Why doesn't this program in C compile? Error: undefined reference to `i2c_smbus_read_byte_data' -

edit: created other topic title , more appropriate/clear details:

how resolve link error "undefined reference `i2c_smbus_read_byte_data'"

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i've tried compile single program in c read , write device through i2c bus i'm getting error:

error: undefined reference i2c_smbus_read_byte_data 

i have installed these packages: libi2c-dev , i2c-tools.

i'm using ubuntu , arm-linux-gnueabi-gcc compiler (cross compile eclipse luna ide)

here whole code:

/* http://www.zerozone.it/2014/05/primi-esperimenti-con-la-beaglebone-black-collegare-10dof-via-i2c/  dof10 i2c test program  v0.1 - 05.05.2014  wrote program test dof10 funcionality beaglebone black.  can buy dof10 module , beaglebone ebay few dollars...have fun !  written michele <o-zone@zerozone.it> pinassi  blog @ www.zerozone.it  feel free use code want. no warranty, in case: use @ own risks !  */  #include <stdio.h> #include <fcntl.h> #include <errno.h> #include <linux/i2c-dev.h> #include <linux/i2c.h>  #define debug  #define l3g4200d_i2c_addr 0x69 #define adxl345_i2c_addr 0x53  typedef signed char s8; typedef unsigned char u8; typedef signed short s16; typedef unsigned short u16; typedef signed int s32; typedef unsigned int u32; typedef signed long s64; typedef unsigned long u64;  int i2chandle; // bus i2c file handle  int i2c_setaddress(unsigned char deviceaddr) {     if (ioctl(i2chandle, i2c_slave, deviceaddr) < 0) {         printf("error while set i2c address 0x%x: %d error\n",deviceaddr,errno);     return -1;     }     return 0; }  unsigned char i2c_readbyte(unsigned char deviceaddr,unsigned char regaddr) {     unsigned char res;      i2c_setaddress(deviceaddr);      res = i2c_smbus_read_byte_data(i2chandle,regaddr);  #ifdef debug     printf("[debug] 0x%x @ 0x%x => 0x%x\n",deviceaddr,regaddr,res); #endif      return res; }  int i2c_writeword(unsigned char deviceaddr, __u8 regaddr, __u16 value) {     int res;      i2c_setaddress(deviceaddr);      res = i2c_smbus_write_word_data(i2chandle, regaddr, value);     if(res < 0) {     printf("error writing 0x%x 0x%x register on i2c bus\n",value, regaddr);     return -1;     }     return 1; }  int i2c_writebyte(unsigned char deviceaddr, __u8 regaddr, __u8 value) {     int res;      i2c_setaddress(deviceaddr);      res = i2c_smbus_write_byte_data(i2chandle, regaddr, value);     if(res < 0) {     printf("error writing 0x%x 0x%x register on i2c bus\n",value, regaddr);     return -1;     }     return 1; }  // 0: 250 dps - 1: 500 dps - 2: 2000 dps int l3g4200d_init(char fullscale) {     if(i2c_readbyte(l3g4200d_i2c_addr,0x0f)!=0xd3) {     printf("error communicating l3d4200d !\n");     return -1;     }      // enable x, y, z , turn off power down:     i2c_writebyte(l3g4200d_i2c_addr, 0x20, 0b00001111);      // if you'd adjust/use hpf, can edit line below configure ctrl_reg2:     i2c_writebyte(l3g4200d_i2c_addr, 0x21, 0b00000000);      // configure ctrl_reg3 generate data ready interrupt on int2     // no interrupts used on int1, if you'd configure int1     // or int2 otherwise, consult datasheet:     i2c_writebyte(l3g4200d_i2c_addr, 0x22, 0b00001000);      // ctrl_reg4 controls full-scale range, among other things:     fullscale &= 0x03;     i2c_writebyte(l3g4200d_i2c_addr, 0x23, fullscale<<4);      // ctrl_reg5 controls high-pass filtering of outputs, use if you'd like:     i2c_writebyte(l3g4200d_i2c_addr, 0x24, 0b00000000); }  void l3g4200d_getgyrovalues() {     int x,y,z;      x = (i2c_readbyte(l3g4200d_i2c_addr, 0x29)&0xff)<<8; // msb     x |= (i2c_readbyte(l3g4200d_i2c_addr, 0x28)&0xff); // lsb      y = (i2c_readbyte(l3g4200d_i2c_addr, 0x2b)&0xff)<<8;     y |= (i2c_readbyte(l3g4200d_i2c_addr, 0x2a)&0xff);      z = (i2c_readbyte(l3g4200d_i2c_addr, 0x2d)&0xff)<<8;     z |= (i2c_readbyte(l3g4200d_i2c_addr, 0x2c)&0xff);      printf("l2d4200d = x:%d y:%d z:%d\n",x,y,z); }  void adxl345_init() {     // set +/- 4g range writing value 0x01 data_format register.     i2c_writebyte(adxl345_i2c_addr,0x31,0x01);      // put adxl345 measurement mode writing 0x08 power_ctl register.     i2c_writebyte(adxl345_i2c_addr,0x2d,0x08); }  void adxl345_readaccel() {     int x,y,z;     // each axis reading comes in 10 bit resolution, ie 2 bytes. lsb first, msb next      x = (i2c_readbyte(adxl345_i2c_addr, 0x33)&0xff)<<8; // msb     x |= (i2c_readbyte(adxl345_i2c_addr, 0x32)&0xff); // lsb      y = (i2c_readbyte(adxl345_i2c_addr, 0x35)&0xff)<<8; // msb     y |= (i2c_readbyte(adxl345_i2c_addr, 0x34)&0xff); // lsb      z = (i2c_readbyte(adxl345_i2c_addr, 0x37)&0xff)<<8; // msb     z |= (i2c_readbyte(adxl345_i2c_addr, 0x36)&0xff); // lsb      printf("adxl345 = x:%d y:%d z:%d\n",x,y,z); }  void main(int argc, char *argv[]) {     char filename[20];      printf("open i2c bus...");      snprintf(filename, 19, "/dev/i2c-1");     i2chandle = open(filename, o_rdwr);     if (i2chandle < 0) {         printf("error while opening device %s: %d error\n",filename,errno);         exit(1);     }      printf("ok !\ninitializing l3g4200d...");     l3g4200d_init(2);      printf("ok !\ninitializing adxl345...");     adxl345_init();      printf("ok !\n");      while(1) {     l3g4200d_getgyrovalues();     adxl345_readaccel();     sleep(1);     }      close(i2chandle); } 

if library installed looks linker issue means.
can verify i2c_smbus_read_byte_data() defined in

linux/drivers/i2c/i2c-core.c 

and has function prototype in,

include/linux/i2c.h 

so may

#include <linux/i2c.h>