Re: Bug: Win32 GTK binaries and Cygwin heap error

[Charles Wilson <cwilson at ece dot gatech dot edu>]

Tim Renner wrote:

> Unfortunately, we have a case where we need to use Cygwin to compile our 
> project because we need the unix and posix support, so -mno-cygwin is 
> out... AND we need to link to GTK libraries that do not require an 
> X-server.  What gets me though is that this DOES work with the older 
> dll, but not with the newer ones...  I'd like to know what changed to 
> cause this difference and if it is a bug or if we just got lucky with 
> the old version ;)

You got VERY lucky. I'd bet that even then, there were subtle bugs 
(memory corruption, races, etc) that were under your radar.

> What I'm seeing for dependencies (Using depends.exe on my test program) 
> is that it depends on Cygwin1.dll and kernel32.dll, as well as 
> libgtk-win32-2.0-0.dll, which does depend on msvcrt.dll, but not 
> cygwin1.dll.  I'm no expert on dll's, so I don't know if that will cause 
> a problem, but from what I understand, that seems okay?

Nope.  Simple example: your app calls printf() which is satisfied via 
cygwin1.dll.  Then, your app calls g_printf (which eventually calls 
system printf -- but in this case, is satisfied by msvcrt.dll).

Which runtime owns stdout?  Do you see both messages, or only one? 
Which one?  Which message is printed first?  Is it *always* printed 
first, or random?  Or do the two messages get intermingled character by 
character?  Or does the app crash? Or deadlock?

------------

It should be possible to 'coopt' the existing MS windowing code from the 
'native' port, to compile a cygwin-based, but MSwindow-not-Xwindow gtk. 
 Tor has two separate #defines throughout the code -- one indicates 
'windowing' and the other indicates 'platform'; you want the first, but 
not the second.  However, no one has attempted to fix the configury bits 
so that you can build gtk as:

  ./configure --without-x --with-mswin

on a cygwin-based (e.g. not MSYS/mingw) system.  If you're willing to 
put in the elbow grease to solve your problem "The Right Way", I'm sure 
Tor will be receptive to your efforts.

FWIW, I posted a patch and method to build glib-2.2.0 on cygwin a few 
months back; that should help a little.  Then you need a non-X but 
cygwin-based libfreetype (being careful not to conflict with the 
existing cygwin-based,X-based libfreetype distributed with 
cygwin-xfree), and then pango, atk, and finally gtk.  It's a big job - 
which is why nobody has done it.

--Chuck



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