sinf compiler error I don't understand (corrected)

[les]

On Fri, 2011-04-01 at 15:29 -0700, les wrote:
> First let me say, that while I have used C++ I don't normally use it for
> my work and so am not throughly familiar with what it does, so if this
> is due to a C++ error, please be gentle.
> 
> I am working on some DSP code I developed a long time ago, and now want
> to port it to 64 bit.  I have read several articles on the differences
> in C and C++ between 32 and 64 bit, but this has me stymied.
> 
> Here is the smallest sample I have been working with to show the current
> error:
> 
> #include <math.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <string.h>
> 
> main()
> {
>     long double temp;
>     printf ("M_PI=%e\n",M_PI);
>     printf ("sin 90 = %e\n",sinf(M_PI/2));
>     temp=M_PI/2.0;
> // the following line won't compile for temp 
> // regardless of how temp is declared (float, double, long double)
> //   printf ("sin 90 = %e\n",sinf(temp));
> }
> 
> 
> Clearly sinf is recognized, and compiles and runs.  It returns 1.000 as
> expected for M_PI/2.  But the line that is commented out will not
> compile.
> 
> If you can see the issue here, please let me know.
> 
> MY system is:
> Release Kernel Linux 2.6.35.11-83.fc14.x86_64 ****** fixed *****
> GNOME 2.32.0
> Hardware
> 	Memory 7.8GiB
> 	AMD Phenom(tm) II X6 1035T
> Lots of disk space
> 
> yum info GCC shows:
> Name        : gcc
> Arch        : x86_64
> Version     : 4.5.1
> Release     : 4.fc14

missing command and error message:
 gcc -ggdb mathck.c
/tmp/ccTdnf1Z.o: In function `main':
/home/lesh/Code/C/arb_wav_file/mathck.c:14: undefined reference to
`sinf'
collect2: ld returned 1 exit status


> 
> Thanks,
> Les H
>