View Full Version : compiation of sqrt funtion in C

June 10th, 2012, 12:29 PM
i have written a program,
were i have to find a square root of a function.
but i get the following error while compilation.

dharmesh@dharmesh-ThinkPad-SL400:~/bg/ch5$ gcc -Wall p10.c -o p10.o
/tmp/cckBRHAS.o: In function `main':
p10.c:(.text+0xf0): undefined reference to `sqrt'
p10.c:(.text+0x134): undefined reference to `sqrt'
collect2: ld returned 1 exit status

i have used the header file math.h, and can't find any error in my simple program,
kindly give a sol to my problem!

June 10th, 2012, 01:30 PM
Probably you need to add -lm for the linker. Say that your file sqrt.c contains the following code

/* Square root of a number using Built-In Function */

#include <stdio.h>
#include <math.h>

void main()
double n,r;
double sqrt(double n);
printf("Enter the no.: ");
printf("The root of %6.4lf is %6.4lf",n,r);

Then you can compile and link it with the following command line

cc -o sqrt sqrt.c -lm