Error: undefined reference to ndbm functions

Joel Sherrill joel at rtems.org
Fri Jun 28 12:48:53 UTC 2019


On Fri, Jun 28, 2019, 8:40 AM Vaibhav Gupta <vaibhavgupta40 at gmail.com>
wrote:

>
>
> On Fri, Jun 28, 2019, 5:57 PM Joel Sherrill <joel at rtems.org> wrote:
>
>> You need to add the library to the gcc command that links the program. If
>> the libndbm is in the library search path, add -lndbm.
>>
>> I don't recall the exact Makefile variable to set for this to show up.
>> Look at the paranoia sample. It should be doing this with -lm.
>>
>> --joel
>>
> Okay, I will try this!
>

The following web page is a pretty good description of building a library
using a native GCC and linking it into a program. It includes some of the
theory going on so this might help you.

https://www.cs.swarthmore.edu/~newhall/unixhelp/howto_C_libraries.html

Guys.. this comes up periodically, even though this is really basic tool
usage to me, is this something we should provide some guidance on?

--joel

>
>> On Fri, Jun 28, 2019, 8:12 AM Vaibhav Gupta <vaibhavgupta40 at gmail.com>
>> wrote:
>>
>>> Hello,
>>> .
>>> Status:
>>>
>>>    1. I have ported ndbm in newlib. When compiled newlib-cygwin,
>>>    function symbols were generated. Created patch.
>>>    2. Applied the patch to RSB and rebuild toolchain. Generated ndbm.h
>>>    in 5/sparc-rtems5/include directory.
>>>
>>> Blocker:
>>>
>>>    1. I made a raw program which calls dbm_open, dbm_close, dbm_store,
>>>    dbm_fetch.
>>>    2. When  I run 'make -j 2', in erc32 directory, it shows undefined
>>>    reference to those functions.
>>>
>>> https://github.com/VARoDeK/rtems/compare/test_ndbm_presence_02
>>> .
>>> home/varodek/development/rtems/5/lib/gcc/sparc-rtems5/7.4.1/../../../../sparc-rtems5/bin/ld:
>>> psxinttypes01/psxinttypes01-init.o: in function `Init':
>>> /home/varodek/development/rtems/kernel/rtems/c/src/../../testsuites/psxtests/psxinttypes01/init.c:231:
>>> undefined reference to `dbm_open'
>>> /home/varodek/development/rtems/5/lib/gcc/sparc-rtems5/7.4.1/../../../../sparc-rtems5/bin/ld:
>>> /home/varodek/development/rtems/kernel/rtems/c/src/../../testsuites/psxtests/psxinttypes01/init.c:232:
>>> undefined reference to `dbm_store'
>>> /home/varodek/development/rtems/5/lib/gcc/sparc-rtems5/7.4.1/../../../../sparc-rtems5/bin/ld:
>>> /home/varodek/development/rtems/kernel/rtems/c/src/../../testsuites/psxtests/psxinttypes01/init.c:236:
>>> undefined reference to `dbm_fetch'
>>> /home/varodek/development/rtems/5/lib/gcc/sparc-rtems5/7.4.1/../../../../sparc-rtems5/bin/ld:
>>> /home/varodek/development/rtems/kernel/rtems/c/src/../../testsuites/psxtests/psxinttypes01/init.c:239:
>>> undefined reference to `dbm_close'
>>> collect2: error: ld returned 1 exit status
>>> make[5]: *** [Makefile:7679: psxinttypes01.exe] Error 1
>>> make[5]: Leaving directory
>>> '/home/varodek/development/rtems/kernel/erc32/sparc-rtems5/c/erc32/testsuites/psxtests'
>>> make[4]: *** [Makefile:663: psxtests] Error 2
>>> make[4]: *** Waiting for unfinished jobs....
>>> .
>>> .
>>> .
>>> Maybe I have compiled it incorrectly, please verify.
>>>
>>>    1. ndbm port: https://github.com/VARoDeK/newlib/compare/port_ndbm
>>>    2. RSB patch:
>>>    https://github.com/VARoDeK/rsb/compare/newlib_ndbm_rsb_patch_01
>>>
>>> Vaibhav Gupta
>>>
>>
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