Re: [sr #106237] Newbie: libltdl not matching #include <ltdl.h>

[Ken Dickey]

[Sorry,  I m not able to log onto the libtool site at present.]

Let me try again.

I would like to dynamically load C libraries and use them.  I am attempting to 
use libltdl for this purpose as I prefer a cross/multi-platform solution.

I am attempting to follow "How to use libltdl in your programs".

My minimal example is ["test.c"]:
/*=============vvvv==============*/
#include <ltdl.h>
int main() {
  int init_status;
  LTDL_SET_PRELOADED_SYMBOLS();
  init_status = (int)lt_dlinit() ;
  return( lt_dlexit() );
}
/*=============^^^==============*/

Using the flags of the runtime build [I did not write the runtime] yields:

>> gcc -g -O2 -DNDEBUG -O3 -Wall -DDYNAMIC_LOADING_SUPPORTED -rdynamic -o 
test -lgmp -lm -ldl -lltdl test.c
/tmp/ccG6urRv.o: In function `main':
/usr/local/src/FFI/test.c:4: undefined reference to `lt_preloaded_symbols'
collect2: ld returned 1 exit status

I see nothing in 
     http://www.gnu.org/software/libtool/manual.html#Dlpreopening
which leads me to a solution which works [I did try adding "-export-dynamic" 
with the same result].

Again, I typically use dynamic languages (Scheme, Smalltalk, Dylan, 
CommonLisp) and it has been some years since I have programmed in C.  I am 
writing this code to build a "foreign function interface" so that I can write 
code which dynamically loads and uses C libraries but does not require 
invocation of a C compiler. 

My eyes glaze over after reading several screens of gcc flag definitions, so 
my understanding their use is pretty basic.

I would appreciate a working example here.

Thanks again for any help,
-KenD










=======================================
On Monday 28 January 2008 11:12:44 am Peter O'Gorman wrote:
> Update of sr #106237 (project libtool):
>
>                   Status:                    None => Invalid
>              Assigned to:                    None => pogma
>              Open/Closed:                    Open => Closed
>
>     _______________________________________________________
>
> Follow-up Comment #1:
>
> Please see http://www.gnu.org/software/libtool/manual.html#Dlpreopening
>
> It should fix your issue, if not feel free to bring it up again on
> address@hidden
>
>
>     _______________________________________________________
>
> Reply to this item at:
>
>   <http://savannah.gnu.org/support/?106237>
>
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