help with dl module and clang

[Daniel Braniss]

> On 3 Nov 2018, at 18:35, Konstantin Belousov <kostikbel at gmail.com> wrote:
> 
> On Sat, Nov 03, 2018 at 06:11:19PM +0200, Daniel Braniss wrote:
>> 
>> 
>>> On 3 Nov 2018, at 17:58, Daniel Braniss <danny at cs.huji.ac.il> wrote:
>>> 
>>> 
>>> 
>>>> On 3 Nov 2018, at 17:47, Dimitry Andric <dim at FreeBSD.org> wrote:
>>>> 
>>>> On 3 Nov 2018, at 15:51, Daniel Braniss <danny at cs.huji.ac.il> wrote:
>>>>> 
>>>>> I have a program that loads some modules via dlopen(),  these modules call some routines
>>>>> which are in the main program, this works when using gcc, but with cc it does not.
>>>>> 
>>>>> when compiling the main program I use  -export-dynamic, and the modules link fine when compiled with
>>>>> gcc, but when compiling with clang/cc i get dlerror: ...Undefined symbol …
>>>>> BTW, when linking the main program with cc I get
>>>>> 	/usr/bin/ld: warning: cannot find entry symbol xport-dynamic; defaulting to 0000000000402140
>>>> 
>>>> Instead of using -export-dynamic (which is a linker flag) as a flag to
>>>> cc, try using -Wl,-export-dynamic instead.  Now, the linker interprets
>>>> this as the -e flag, which is something totally different.
>>>> 
>>> 
>>> i had tried that before but i had -WI (upper case i) but re-reading the manual
>>> it should be-Wl (lower case l as in lima :-))!!!!!
>>> 
>>> thanks!!!!!!
>>> 
>>> and now have to try profiling (gprof) which started this mess,
>>> 
>>> thanks again!!
>>> 
>>> danny
>>> 
>>> 
>>>> I think this will also help with the exporting of the symbols of your
>>>> main program.
>>>> 
>>>> -Dimitry
>>>> 
>>> 
>> ok, new problem, it also happens with gcc:
>> 
>> when compiling the main program with flag -pg (gprof)
>> dlopen fails with dlerror: Service unavailable
> This means that your binary is linked statically.
> dlopen(3) is not supported for static linking, ld-elf.so.1 is required
> for dynamic loading to work.

as far as I can tell, it’s NOT statically linked:
l
e-kots-b# ldd /vol/src/libexec/idng/idngd/idngd 
/vol/src/libexec/idng/idngd/idngd:
       libpq.so.5 => /usr/local/lib/libpq.so.5 (0x800932000)
       libcrypto.so.8 => /lib/libcrypto.so.8 (0x800c00000)
       libldap-2.4.so.2 => /usr/local/lib/libldap-2.4.so.2 (0x801070000)
       libthr.so.3 => /lib/libthr.so.3 (0x8012b7000)
       libintl.so.8 => /usr/local/lib/libintl.so.8 (0x8014df000)
       libssl.so.8 => /usr/lib/libssl.so.8 (0x8016ea000)
       libc.so.7 => /lib/libc.so.7 (0x80195d000)
       liblber-2.4.so.2 => /usr/local/lib/liblber-2.4.so.2 (0x801d18000)
e-kots-b# file !$
file /vol/src/libexec/idng/idngd/idngd
/vol/src/libexec/idng/idngd/idngd: ELF 64-bit LSB executable, x86-64, version 1 (FreeBSD), dynamically linked, interpreter /libexec/ld-elf.so.1, for FreeBSD 11.2 (1102501 <tel:1102501>), FreeBSD-style, not stripped


> 
>> 
>> what magic is needed now?
>> 
>> danny
>> 
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