Re: sqrt C function

[David Purton <dcpurton@chariot.net.au>]

On Fri, 10 Aug 2001 R1nso13@aol.com wrote:

> when i try to use the sqrt function in gcc 3.0, and the gcc that's standard 
> with 2.2r3 ( i forget the version)  i get errors. here's some example code:
> 
> #include <math.h>
> #include <stdio.h>
> 
> double num;
> double num_root;
> 
> int main ()
> {
>     num = 4;
>     num_root = sqrt(num);
>     return (0);
> }
> 
> fails to compile. i've tried using double as well as float variables. i'm 
> sure this is due to poor coding, but i'm looked at the man page and 
> linuxdoc.org and cannot find any example implementations of sqrt(). I'm 
> running i386 arch, and have math.h (as well as the complete gcc 3.0) 
> installed.


Does the error occur during the compile or link stage?

you need to link with the math library

the code above compiles fine for me using this command

 $ gcc -o test test.c -lm


cheers

dc


--------------------------------------------------------
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David Purton

http://www.chariot.net.au/~dcpurton/
dcpurton@chariot.net.au