Re: -lm not required when including functions from math.h

Re: -lm not required when including functions from math.h

[Harvey Muller]

Eljay,

That helped enormously, thanks for the pointer.  They are indeed built into the
compiler.  Now I know to use -fno-builtin and -lm if I specifically want to use libm.a,
and more importantly, why.

Best regards,

Harvey

----- Original Message ----
> From: Eljay Love-Jensen <eljay@adobe.com>
> To: Harvey Muller <hlmuller@yahoo.com>; GCC-help <gcc-help@gcc.gnu.org>
> Sent: Friday, June 27, 2008 1:06:32 PM
> Subject: Re: -lm not required when including functions from math.h
> 
> Hi Harvey,
> 
> Some math functions are built into the compiler.
> 
> Some math functions are macros in the math.h header.
> 
> Some platforms include -lm (or the analogous equivalent) for you.
> 
> HTH,
> --Eljay

Re: -lm not required when including functions from math.h

[Eljay Love-Jensen]

Hi Harvey,

Some math functions are built into the compiler.

Some math functions are macros in the math.h header.

Some platforms include -lm (or the analogous equivalent) for you.

HTH,
--Eljay

-lm not required when including functions from math.h

[Harvey Muller]

I'm learning C programming using the GNU toolchain (gcc, as, ld, glibc) using a popular linux distribution.  What I expect from what I have read so far, is that if I use a function from the math library without specifying the library on the gcc, command line, is that I should get an "undefined reference" error message.
I am not getting the expected error message, the simple application compiles and executes correctly.  Can anyone explain why I am not getting the expected error message?
Best regards,
Harvey