Re: Problems with math.h

[Zoran Cutura <cutura at str dot daimler-benz dot com>]

tobias_meier@my-deja.com wrote:
> 
> Hi all,
> 
> compiling this program with the command:
> 
> gcc MatheTest.c
> 
> /* Program MatheTest.c*/
> #include <stdio.h>
> #include <stdlib.h>
> #include <float.h>
> #include <math.h>
> 
> main()
> {
> printf("Ergebnis %f \n", exp(2.3));
> printf("Ergebnis %f \n", pow(2,3));
> }
> 
> /* End Program */
> 
> I get:
> 
> cd /home/tmeier/C/Projekt01/
> gcc MatheTest.c
> /tmp/ccdP8Uys.o: In function `main':
> /tmp/ccdP8Uys.o(.text+0xe): undefined reference to `exp'
> /tmp/ccdP8Uys.o(.text+0x37): undefined reference to `pow'
> collect2: ld returned 1 exit status
> 
> Compilation exited abnormally with code 1 at Thu Jan  6 22:27:58
> 
>  -> problems with math.h
> 
> looking up search dirs with command:
> 
> gcc -print-search-dirs
> 
> I get:
> 
> install: /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/
> programs: /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/:/usr/lib/gcc-
> lib/i486-linux/:/usr/lib/gcc/i486-linux/egcs-2.91.60/:/usr/lib/gcc/i486-
> linux/:/usr/i486-linux/bin/i486-linux/egcs-2.91.60/:/usr/i486-linux/bin/
> libraries: /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/:/usr/lib/gcc/i486-
> linux/egcs-2.91.60/:/usr/i486-linux/lib/i486-linux/egcs-
> 2.91.60/:/usr/i486-linux/lib/:/usr/lib/i486-linux/egcs-
> 2.91.60/:/usr/lib/:/lib/i486-linux/egcs-2.91.60/:/lib/:/usr/lib/i486-
> linux/egcs-2.91.60/:/usr/lib/
> 
> searching math.h I get:
> /usr/include/math.h
> 
> Ok, using option -B for gcc:
> 
> gcc -B /usr/include/math.h MatheTest.c
> 
> I get:
> 
> cd /home/tmeier/C/Projekt01/
> gcc -B /usr/include/math.h MatheTest.c
> /tmp/ccOFzmvH.o: In function `main':
> /tmp/ccOFzmvH.o(.text+0xe): undefined reference to `exp'
> /tmp/ccOFzmvH.o(.text+0x37): undefined reference to `pow'
> collect2: ld returned 1 exit status
> gcc: file path prefix `/usr/include/math.h' never used
> 
> Compilation exited abnormally with code 1 at Thu Jan  6 22:41:52
> 
> Compiling with g++ works:
> 
> But g++ has the same search path as gcc has !
> 
> g++ serch dirs (g++ -print-search-dirs)
> install: /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/
> programs: /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/:/usr/lib/gcc-
> lib/i486-linux/:/usr/lib/gcc/i486-linux/egcs-2.91.60/:/usr/lib/gcc/i486-
> linux/:/usr/i486-linux/bin/i486-linux/egcs-2.91.60/:/usr/i486-linux/bin/
> libraries: /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/:/usr/lib/gcc/i486-
> linux/egcs-2.91.60/:/usr/i486-linux/lib/i486-linux/egcs-
> 2.91.60/:/usr/i486-linux/lib/:/usr/lib/i486-linux/egcs-
> 2.91.60/:/usr/lib/:/lib/i486-linux/egcs-2.91.60/:/lib/:/usr/lib/i486-
> linux/egcs-2.91.60/:/usr/lib/
> 
> Who knows what to do ?
> 
> Sent via Deja.com http://www.deja.com/
> Before you buy.

-lm 

will link libm.a to yout executable!
Bye
	Z