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Date: Mon, 08 Apr 2002 16:05:40 -0400
To: fmotta AT embedded-guru DOT com
From: "Larry Hall (RFK Partners, Inc)" <lhall AT rfk DOT com>
Subject: Re: Problem with dlopen
Cc: <cygwin AT cygwin DOT com>
In-Reply-To: <30060.65.200.9.2.1018045910.squirrel@portal.embedded-guru.
 com>
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At 06:31 PM 4/5/2002, Frank Motta wrote:
>Thanks Larry,
>     As a result of your response I made a -very- truncated version and got
>past the dlopen error.
>
>     The problem seems to be in the -creation- of the dll.
>
>     the instructions at http://cygwin.com/cygwin-ug-net/dll.html result in
>many link-time errors and the method I -was- using (see below) does not
>export the symbol I need.
>
>     Any ideas?


Yes.  See below.


>from makefile clip 8<-----------------------------
># This creates a dll without the exports I need - see def below
>TARGET=simpletest
>DLL_SUFF=.dll
>LIB_SUFF=.a
>DLL_EXP_LIB =$(TARGET)$(DLL_SUFF)$(LIB_SUFF)
>DLL_NAME=$(TARGET)$(DLL_SUFF)
>INCLUDE=
>
>simpletest.dll: Makefile simpletest.o
>         gcc -shared -Wl,--out-implib=$(DLL_EXP_LIB) -o $(DLL_NAME)
>$(DLL_OBJS) $
>(DLL_LDFLAGS) $(DLL_LDLIBS) -Wl,--export-all
>         dlltool --def simpletest.def --dllname simpletest.dll --output-lib

                        ^^^^^^^^^^^^^^

>simpletest.a
>
>simpletest.o: simpletest.c ../../modules.h ../../global.h ../../types.h
>         $(CC) $(INCLUDE) -c simpletest.c
>
>------------------------------------- >8 clip makefile
>
>from test.def clip 8< ----------------------------------------

       ^^^^^^^^

Oops!


>EXPORTS
>mod_import
>------------------------------------ >8 clip test.def
>
>from simpltest.c 8< ---------------------------------------------------
>
>void *foo();
>void *(*export_foo)() = foo;
>void *mod_import(char **argv) {
>    return export_foo;
>}
>
>char *hello = "hello world";
>void *foo() {
>         return (void *) hello;
>}
>------------------------------------ >8 clip test.c
>from nm simpletest.dll | grep T clip 8< ------------------------------
>100010f4 T _DllMain AT 12
>100012a4 T _GetModuleHandleA AT 4
>100012ac T __CTOR_LIST__
>100012b4 T __DTOR_LIST__
>100012ac T ___CTOR_LIST__
>100012b4 T ___DTOR_LIST__
>1000113c T __cygwin_crt0_common AT 8
>10001024 T __cygwin_dll_entry AT 12
>100010d4 T __cygwin_noncygwin_dll_entry AT 12
>10001000 T __end__
>1000125c T _calloc
>1000110c T _cygwin_attach_dll
>10001104 T _cygwin_detach_dll
>1000129c T _cygwin_internal
>10001294 T _cygwin_premain0
>1000128c T _cygwin_premain1
>10001284 T _cygwin_premain2
>1000127c T _cygwin_premain3
>10001254 T _dll_dllcrt0
>10001000 T _end
>1000126c T _free
>10001274 T _malloc
>10001264 T _realloc
>10001000 T end
>100012bc T etext
>--------------------------------------------- >8 nm output
>
>Notice the -lack- of mod_import!!!
>
>
>
>
>Thanks !!!!
>
>
>
><Larry Hall (RFK Partners, Inc)>
> > At 02:51 PM 4/5/2002, Frank Motta wrote:
> >>The following code returns Win32 error 126 - this is the same error I get
>if I try a file which does not exist.
> >>
> >>What is going wrong (operator malfunction - I'm sure!)
> >>please help
> >>             strncat(mod_file_name, LIB_EXT, LIB_EXT_LEN + 1);
> >>             // FJM handle = dlopen(mod_file_name, (RTLD_NOW |
> >>             RTLD_GLOBAL)); handle = dlopen(mod_file_name,
> >>             (DLOPEN_MODE));
> >>             if ((err = dlerror()) == NULL) { break; }
> >
> >
> > $ net helpmsg 126
> > The specified module could not be found.
> >
> > With the information you've given, one can only say mod_file_name is not
>where you say it is.  If that's the issue, it's not a Cygwin problem and
>would be off-topic for this list.  If that's not the problem, you'll need
>to provide more information about the specifics.  Results from debugging
>into Cygwin or even output from running your program under strace would be
>useful to further any pertinent
> > discussion.
> >
> >
> >
> > Larry Hall                              lhall AT rfk DOT com
> > RFK Partners, Inc.                      http://www.rfk.com
> > 838 Washington Street                   (508) 893-9779 - RFK Office
>Holliston, MA 01746                     (508) 893-9889 - FAX
>
>
>-- 
>Frank Motta
>fmotta AT embedded-guru DOT com
>
>If you cannot recognize divinity in your fellow man, then you will not
>realize the devine within yourself...
>


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