Subject: RE: Re[2]: Linking with .LIB files
From: [email-masked] (Colin Peters)

28 Mar 1997 02:20:28 -0800
Approved: [email-masked]
Distribution: cygnus
Message-ID: <01BC3AA2.3D63E0C0.cygnus.gnu-win32@gbird0>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Original-To: "'David W Palmer'" <[email-masked]>
Original-Cc: "'GNU-Win32'" <[email-masked]>
Original-Sender: [email-masked]

David W Palmer[SMTP:[email-masked]] wrote:
>     For those who are watching: Colin Peter's text is left justified, mine is 
>     indented.
>
>David W Palmer[SMTP:[email-masked]] wrote:
>Although this may be secondary to your concerns, or in fact may be 
>totally off topic, I notice that libglu32.a and libopengl32.a are 
>both included with the beta 17.1 distribution. I'm not sure about 
>the header files, but if you can get your code to compile you should 
>be able to link it with ld. Of course this doesn't help if what you 
>really want is DirectX or some other thing that comes with .lib 
>files you can't convert to .a files.
>     
>     Actually, that is interesting.  From the distribution I downloaded, 
>     libglu32.a and libopengl32.a are not available.  However, I am 
>     interested in the general problem of linking with MS lib's (ie, 
>     glaux.lib).
>     
>     I suspect that I could use dlltool to generate an import library for 
>     glu32.dll and opengl32.dll.  I'll give it a try.

Actually I've got libglaux.a as well. Hang on a second and I'll look at
my original copy... they are definitely there. So it doesn't seem I
generated them myself later. In the original tarball I found them in
H-i386-cygwin32/i386-cygwin32/lib. Interestingly some of these (but
not all) have .def files included in the original Win32-API 0.1.2
package. In the Cygnus source distribution the def files appear in
src/winsup/sysdef/i386, and that should be all of them.

But back to the question of linking with .libs that you can't get
a .a for...

>>      LINK : error LNK2001: unresolved external symbol _WinMainCRTStartup 
[snip: include crt0.o?]
>     //f/pgming/OpenGL/simple$ make
>     link simple.o crt0.o libuser32.a glu32.lib opengl32.lib libgdi32.a 
>     /subsystem:windows /machine:i386
>     crt0.o : error LNK2001: unresolved external symbol _cygwin_crt0

Hmm, that would be in libcygwin32.a if I remember correctly.

>     So, I can trade WinMainCRTStartup() for cygwin_crt0().  Not much 
>     progress.  Though, this has to be defined somewhere!  Which library?  
>     Unfortunately, I don't know how to list the functions in a library. 
>     (how embarrassing) :+(

You can get a list of functions in a library fairly easily by using
nm (which lists symbol names):

  nm libfoo.a | grep T

Of course with sed and awk, or possibly the correct options to
nm (!) you can probably get cleaner output, but this is a useful
first cut. I often use nm libfoo.a | grep foobar to see if foobar
is in the foo library.

>     BTW: instead of defining WinMainCRTStartup(), it's easier to use the 
>     link option /ENTRY:mainCRTStartup.

This is true.

It seems from following other threads on this matter that the
whole effort may be doomed by some sort of "offset problem"
people seem to have with programs linked this way. Although
my memory may be failing me again. I have some information
which leads me to believe a bug in gas (or as if you like;
the assembler) may hurt your chances of getting this to work.

But anyway, good luck,

Colin.

-- Colin Peters - [email-masked]
-- Saga University Dept. of Information Science
-- http://www.fu.is.saga-u.ac.jp/~colin/index.html
-- http://www.geocities.com/Tokyo/Towers/6162/

-
For help on using this list, send a message to
"[email-masked]" with one line of text: "help".