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Message-ID: <3A37B4FA.984D9F57@ece.gatech.edu>
Date: Wed, 13 Dec 2000 12:42:18 -0500
From: Charles Wilson <cwilson AT ece DOT gatech DOT edu>
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To: John Wiersba <John DOT Wiersba AT medstat DOT com>
CC: cygwin AT sources DOT redhat DOT com
Subject: Re: curses problem trying to build ruby
References: <03F4742D8225D21191EF00805FE62B9904B3F681 AT aa-msg-01 DOT medstat DOT com>
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John Wiersba wrote:
> 
> Charles,
> 
> I simplified the problem a little, to get rid of dllwrap:
> 
>    $ cd ruby-1.6.1/ext/curses
>    $ gcc curses.o -L../.. -lcygwin-ruby16 -lncurses
>    curses.o: In function `free_window':
>    /.../ruby-1.6.1/ext/curses/curses.c:65: undefined reference to `stdscr'
>    ...
> 
> It looks like stdscr is not defined in libncurses.  But,
> 
>    $ cd /usr/lib
>    $ ls -l *cur*
>    lrw-r--r-- 1 jrw JRW     23 Dec 12 18:36 libcurses.a -> libncurses.a
>    lrw-r--r-- 1 jrw JRW     27 Dec 12 18:36 libcurses.dll.a ->
> libncurses.dll.a
>    -rw-r--r-- 1 jrw JRW 277240 Nov 25 00:44 libncurses++.a
>    -rw-r--r-- 1 jrw JRW 392186 Nov 25 00:08 libncurses.a
>    -rw-r--r-- 1 jrw JRW 263752 Nov 25 00:44 libncurses.dll.a
>    -rw-r--r-- 1 jrw JRW   4820 Nov 11 01:32 libsecur32.a
>    $ nm libncurses.a | grep stdscr
>             U _stdscr
>    ...
>             U _stdscr
>    00000000 D _stdscr
>             U _stdscr
> 
> seems to show that it is.

But you're not linking to libncurses.a.  You are linking to
libncurses.dll.a, the dll import lib.  To avoid this, you have to
specify -static.  But that's not the real puzzler.  

/usr/include/ncurses.h defines stdscr thus:
   extern NCURSES_EXPORT_VAR(WINDOW *)   stdscr;
which expands to 
   extern __declspec(dllimport) WINDOW * stdscr;

Short version: curses.o should have the following undefined symbol
              U _imp__stdscr
not
              U _stdscr

And by linking to libncurses.dll.a (the default), the linker will find
__imp__stdscr.

However, it appears that you are including a *different* ncurses.h from
somewhere, because your curses.o is not seeing the __declspec(dllimport)
decoration.  Do you have an old ncurses installed in '/usr/local' ?

If so (and if it's the old cygutils version) remove it using
http://cygutils.netpedia.net/V1.1/usr-local/Obsolete.html  -- but READ
the directions first: you only want to remove /usr/local/---ncurses, not
/usr/local/---everything. (If you have other programs that have been
compile using the /usr/local/---ncurses, you'll need to set
TERMINFO=/usr/share/terminfo to prevent them from looking in
/usr/local/share/terminfo for their terminfo database).

 --Chuck

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