compile error while using dlopen

shriashishpatil · #1 (**permalink**) 03-15-2006

Hi unix lovers,

I am getting error while compile a function which uses dlopen.

My code is

Quote:

$ cat testjvm.c
#include<stdio.h>
#include <dlfcn.h>
#include <link.h>

void main()
{

int retval=0;
retval = (int)dlopen("libjvm.so",RTLD_LAZY);
if(retval == 0)
printf("\nFailed to load JVM Library");
else
printf("\nSuccessfully loaded JVM Library");

}

I am getting error as follows

Quote:

$ cc testjvm.c
Undefined first referenced
symbol in file
dlopen testjvm1.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
ld: fatal: Symbol referencing errors. No output written to a.out
$

Am I missing something? I think I am missing a lot :-)

I am using solaris.

Thanks in advance,
-Ashish

shriashishpatil · #2 (**permalink**) 03-16-2006

I have made few changes in test program. Added errorno and dlerror() just for error checking

Quote:

$
$ cat testjvm2.c
#include <stdio.h>
#include <errno.h>
#include <dlfcn.h>

void main(void)
{

void *handle;

handle = dlopen("libjvm.so", RTLD_LAZY);
if( handle == NULL )
{
printf("errno[%d], errmsg[%s]\n", errno, dlerror());
return;
}
else
{
printf("\nJVM loaded successfully");
}
dlclose(handle);

}
$

when I compile the program I get error

Quote:

$ cc -o testjvm2 testjvm2.c
Undefined first referenced
symbol in file
dlopen testjvm2.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
dlclose testjvm2.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
dlerror testjvm2.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
ld: fatal: Symbol referencing errors. No output written to testjvm2
$

Quote:

$ uname -a
SunOS snvi003 5.8 Generic_117350-20 sun4u sparc SUNW,Sun-Fire-V240
$

any pointers why the linking error?

-Ashish

andryk · #3 (**permalink**) 03-16-2006

Quote:

Undefined first referenced
symbol in file
dlopen testjvm2.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
dlclose testjvm2.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
dlerror testjvm2.o (symbol belongs to implicit dependency /usr/lib/libdl.so.1)
ld: fatal: Symbol referencing errors. No output written to testjvm2

Then you must link it explicitly with dl, try

Code:

 cc -o testjvm2 testjvm2.c -ldl

shriashishpatil · #4 (**permalink**) 03-16-2006

Thanks a lot andryk. It worked on solaris.

I tried the same program on hp-ux.
On hp-ux it fails to load jvm library.

Quote:

$
$ cc -o testjvm testjvm.c
$
$ testjvm
errno[0], errmsg[Can't open shared library: libjvm.sl]
$
$ echo $SHLIB_PATH
/opt/weblogic810sp3/jdk142_03/jre/lib/PA_RISC/server:/crmusr1.pi004/users/cluser/ruchit/clarify/orion01/ClarifyCRMApplications/bin:.:/oravl01/oracle/9.2.0.5/lib32:/usr/lib:/opt/tuxedo/lib:/opt/weblogic810sp3/jdk142_03/jre/lib
$
$ echo $LD_LIBRARY_PATH
/opt/weblogic810sp3/jdk142_03/jre/lib/PA_RISC/server:/crmusr1.pi004/users/cluser/ruchit/clarify/orion01/ClarifyCRMApplications/bin:.:/oravl01/oracle/9.2.0.5/lib32:/usr/lib:/opt/tuxedo/lib:/opt/weblogic810sp3/jdk142_03/jre/lib
$
$ uname -a
HP-UX hppi004 B.11.11 U 9000/800 1834916430 unlimited-user license
$

Any pointers why it is failing on hp-ux?

-Ashish

naren_chella · #5 (**permalink**) 06-29-2006

hi ,
In Hp-Ux , when creating a shred lib we have to use +z option to create an object file for shared lib ,
for ex:
$cc +z -c share.c -o share.o

$ld -b share.o -o share.sl ( to create a shared lib )

Just try this and let me know !

Thanks
Narendra

shriashishpatil · #6 (**permalink**) 06-29-2006

Hi Narenadra,
I am not creating shared library. I am just opening it in my program with statement
retval = (int)dlopen("libjvm.sl",RTLD_LAZY);

-Ashish

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