From mboxrd@z Thu Jan  1 00:00:00 1970
From: llewelly@198.dsl.xmission.com
To: "Jose Miguel A.C.Pires" <jmcp@ci.uminho.pt>
Cc: help-gcc@gnu.org
Subject: Re: Compilation error
Date: Sat, 01 Apr 2000 00:00:00 -0000
Message-ID: <Pine.LNX.4.10.10002211136090.5368-100000@198.dsl.xmission.com>
References: <200002211831.SAA15847@pessoa.ci.uminho.pt>
X-SW-Source: 2000-q1/msg00267.html
Message-ID: <20000401000000.__Zl0YZlmp_SV8MJBzW1FtEh8r1no2kYsaLKntz7arw@z>

On Mon, 21 Feb 2000, Jose Miguel A.C.Pires wrote:

> *This message was transferred with a trial version of CommuniGate(tm) Pro*
> Hello
> 
> I'm trying to compile this simple program
> 
> #include <stdio.h>
> #include <math.h>
> 
> int main(void)
> {
>   float r=2;
> 
>   printf("A raiz de %2.0f e' %.6f", r, sqrt(r));
> 
>   return 0;
> }
> 
> but i get the following errors.
> 
> /tmp/cca110161.o: In function `main':
> /tmp/cca110161.o(.text+0x17): undefined reference to `sqrt'
> 

Add -lm to your link line:

$gcc foo.c -lm

(-lm means 'link libm.[so,a] . libm is the math library.')