Re: [*] about gcc

[Junichi Uekawa <ti0113@mail4.doshisha.ac.jp>]

On 7 Feb 2000 01:09:00 +0800, maths@21cn.com (=?ISO-8859-1?Q?=D5=C5=CF=FE=C0=DA@murphy.debian.org) was crying out from somewhere
  about: [*] about gcc

maths> hello everybody:
maths> 
maths> i am using debian 2.1r4, i install it use deselect's preselect "scientific 
maths> workstation". i found my gcc doesn't allow me to use "sqrt", for example:
maths> 
maths> this is a c file: a.c
maths> 
maths> #include "stdio.h"
maths> #include "math.h"
maths> main(){
maths> printf("%f\n",sqrt(2));
maths> }
maths> 
maths> and execute "cc a.c"
maths> 
maths> i get:
maths> /tmp/ccc00242: In function 'main':
maths> /tmp/ccc00242(.text+0xb): undefined reference to 'sqrt'
maths> 
maths> so i had to use g++ instead, and it worked!
maths> 
maths> i had use this gcc to campile some math software such as "pari", "simath","rlab"...and 
maths> it work very well, not any error reported.
maths> 
maths> what is the problem? 
maths> 

you need to do 

gcc -lm

to link the maths library.

Don't ask me why. 


---------------------------------------------------------------------------
Junichi Uekawa, a.k.a. dancer
 a member of the Dept. of Knowledge Engineering and Computer Science, 
   Doshisha University.
... I pronounce Linux as Day-bee-enne