Re: help!

[Brian Gough <bjg@netsci.freeserve.co.uk>]

Hi,
The library needs to be last on the command line so that it is searched
at the end of the link stage. If you use 

gcc -I -I/usr/local/include -L/usr/local/lib rngtest.c -lgsl -o
rngtest.out

instead of 

gcc -I -I/usr/local/include -L/usr/local/lib -lgsl rngtest.c -o
rngtest.out

then it should work.

regards
Brian Gough


jin min ho wrote:
> 
> please help me with linking gsl!
> until i downloaded gsl-0.4.1 and installed it,it seemed that there was
> no problem with it.
> but when i link my first code to gsl rng, there was an link error.
> it repoted that "undefined reference to gsl_rng_env_setup and etc.
> it seemed that my gcc couldn't find gsl.
> here is my makefile and source code. what's wrong with my code ?
> 
>   ------------------------------------------------------------------------
> 
> my linux box : redhat linux 5.2
> gcc version  : 2.7.2.3
> egcs version : 1.0.3
> 
> my gcc report :
> 
> /tmp/cca017371.o: In function 'main':
> /tmp/cca017371.o(.text+0x4): undefined reference to 'gsl_rng_env_setup'
> /tmp/cca017371.o(.text+0x9): undefined reference to 'gsl_rng_default'
> /tmp/cca017371.o(.text+0xf): undefined reference to 'gsl_rng_alloc'
> /tmp/cca017371.o(.text+0x24): undefined reference to 'gsl_rng_name'
> /tmp/cca017371.o(.text+0x3c): undefined reference to 'gsl_rng_default_seed'
> /tmp/cca017371.o(.text+0x55): undefined reference to 'gsl_rng_get'
> make: *** [rngtest.out] Error 1
> 
> my source code :
> 
> #include <stdlib.h>
> #include <gsl_rng.h>
> 
> gsl_rng *r;
> 
> int main(void)
> {
>   gsl_rng_env_setup();
>   r = gsl_rng_alloc(gsl_rng_default);
> 
>   printf("generator type = %s\n", gsl_rng_name(r));
>   printf("seed           = %u\n", gsl_rng_default_seed);
>   printf("first value    = %u\n", gsl_rng_get(r));
> 
> }
> 
> my makefile
> 
> ARCH = i386
> TOPDIR  := $(shell if [ "$$PWD" != "" ]; then echo $$PWD; else pwd; fi)
> 
> CROSS_COMPILE   =
> 
> AS      =$(CROSS_COMPILE)as
> LD      =$(CROSS_COMPILE)ld
> CC      =$(CROSS_COMPILE)gcc -I$(HPATH)
> CPP     =$(CC) -E
> AR      =$(CROSS_COMPILE)ar
> NM      =$(CROSS_COMPILE)nm
> STRIP   =$(CROSS_COMPILE)strip
> MAKE    =make
> 
> GSL_INC_DIR = /usr/local/include
> GSL_LIB_DIR = /usr/local/lib
> GSL_LIB=gsl
> 
> GSL_OPT = -I$(GSL_INC_DIR) -L$(GSL_LIB_DIR) -l$(GSL_LIB)
> 
> all : rngtest.out
> 
> rngtest.out : rngtest.c /usr/local/include/gsl_rng.h
>         $(CC) $(GSL_OPT) $< -o $*.out