Re: Simple c program won't compile

["Oliver Elphick" <olly@lfix.co.uk>]

Mark Phillips wrote:
  >Hi,
  >
  >The following program:
  >
  >
  >#include <stdio.h>
  >#include <math.h>
  >
  >int main(int argv, char **argc){
  >  double x;
  >
  >  x=sqrt(5.0);
  >}
  >
  >
  >does not compile.  Instead I get the errors:
  >
  >$ gcc thick.c
  >/tmp/ccU9fgSr.o: In function `main':
  >/tmp/ccU9fgSr.o(.text+0x16): undefined reference to `sqrt'
  >collect2: ld returned 1 exit status
  >
  >
  >What is wrong?

Your problem is in the link stage.  sqrt() is part of the maths library and
so you need to add -lm to your compilation options.

-- 
Oliver Elphick                                Oliver.Elphick@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver
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