Re: math.h prob

[Art Haas <arthur.haas@westgeo.com>]

Dave Brennan <9147261b@clinmed.gla.ac.uk> writes:

> Hi,
> 
> I am having problems using maths functions. e.g if I have the program
> 
> #include <stdio.h>
> #include <math.h>
> 
> main()
> {
> double x;
> scanf("%lf",&x);
> printf("x = %lf",sqrt(x));
> }
> 
> and try to compile it using,
> 
> gcc -o test mattest.c
> 
> I get the following error:
> 
> Undefined                       first referenced
>  symbol                             in file
> sqrt                                /var/tmp/cc9Eay_r1.o
> ld: fatal: Symbol referencing errors. No output written to test
> 

You need to link in the math library ...

% gcc -o test mattest.c -lm

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