Help with sqrt() and #include <math.h> and what -l???

Help with sqrt() and #include <math.h> and what -l???

[Ron Hudson]

I want to use sqrt() in my C program, everything compiles but the linker
can't find sqrt()

/tmp/ccUBZv3v.o(.text+0xe36): undefined reference to 'sqrt'

I believe i need a -l<some library> in my makefile but I don't know
how to find out what <some library> is...

ron.

Re: Help with sqrt() and #include <math.h> and what -l???

[Jonathan Wilson]

Depends on the platform.
But, try -lm (to read libm.a) since that seems to be the "standard" on 
things like linux and other unix platforms.

Re: Help with sqrt() and #include <math.h> and what -l???

[Ron Hudson]

-lm works, Thank you.

Now how can I answer that sort of question for myself in future...  I 
looked at the man page for
sqrt and gcc, but they didn't tell me anything.



On Feb 25, 2005, at 6:23 PM, Jonathan Wilson wrote:

> Depends on the platform.
> But, try -lm (to read libm.a) since that seems to be the "standard" on 
> things like linux and other unix platforms.
>
>

Re: Help with sqrt() and #include <math.h> and what -l???

[Jonathan Wilson]

Depends on what OS.
If its linux (or some other unix), the manpages for the function should 
tell you.
If its something else (e.g. mac, windows, etc), I dont know.
But for all the math functions, use -lm

Re: Help with sqrt() and #include <math.h> and what -l???

[corey taylor]

Ron,

http://www.linuxbase.org/spec/refspecs/LSB_1.2.0/gLSB/baselib.html 
has a thorough matching.

http://www.linuxbase.org/spec/refspecs/LSB_1.2.0/gLSB/libm.html libm
interfaces specifically.

I offer this as suggestive information only.

corey


On Sat, 26 Feb 2005 10:45:27 +0800, Jonathan Wilson <jonwil@tpgi.com.au> wrote:
> Depends on what OS.
> If its linux (or some other unix), the manpages for the function should
> tell you.
> If its something else (e.g. mac, windows, etc), I dont know.
> But for all the math functions, use -lm
> 
>