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From: "Dave Korn" <dave DOT korn AT artimi DOT com>
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References: <f3hhrr$qt1$1 AT sea DOT gmane DOT org>
Subject: RE: Slightly off-topic, but...
Date: Tue, 29 May 2007 17:16:12 +0100
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  Sigh.  This post is a fine example of exactly why we're removing the
-mno-cygwin option: for some reason, despite it being very plainly called "no
cygwin", people just refuse to believe that the stuff it creates has NO CYGWIN
in it.

On 29 May 2007 16:46, Eric Lilja wrote:

> Hi, I've installed qt-win-opensource-4.2.3-mingw.exe 

  More than just 'slightly' off-topic then...

> from trolltech and
> I'm using the tools installed by cygwin to develop Qt programs. Well,
> one could argue I'm not really using cygwin because I have to pass
> -mno-cygwin when compiling otherwise I get errors for non-trivial programs.

  You're not using cygwin.  This isn't arguable, it is a non-negotiable fact
of reality.

> Anyway, -mno-cygwin makes the executables dependent on mingwm10.dll
> instead of cygwin1.dll, correct?

  It invokes a mingw cross-compiler and makes your executables MinGW
executables rather than cygwin executables.

  As such, anything they may or may not do is no more relevant here than any
other non-cygwin application such as Word, Excel or Outlook.

  ObTopic:  You can still use 'cygcheck <executable>' to list the dll
dependencies of the executable.

>  Since my QT programs depend on this dll
> I can only start them from a cygwin shell since cygwin itself is not in
> windows path (and I don't think it should be).

  No, they don't need cygwin anywhere, because they are no-cygwin programs,
which means NO CYGWIN.  You would be better off starting them from a DOS
shell, because they might get confused (as all native win32 apps do) if you
were to try launching them from a cygwin shell connected to a unix pty instead
of having their stdin/out/err connected to a win32 console.

  Incidentally, /why/ do you think cygwin shouldn't be in the path?  I always
put it in my win32 path so that I can use things like grep from a DOS shell.

> My question is how safe is it to put mingwm10.dll in the windows path so
> I can start my qt programs from explorer?

  You'd probably be best off to put the dll and the executable in the same
installation directory.  LoadLibrary always looks in the same dir as the
executable for dlls.  Still, you should be entirely safe putting the mingw
dlls in the PATH.

> That would mean having two
> copies of the same dll in the path under cygwin...which I know is bad
> for cygwin1.dll.

  Which is still completely irrelevant to this completely off-topic post.
But, yes, it's a bad idea, so don't do it.

> Any comments welcome...sorry for being off-topic, but maybe this is of
> interest to people using cygwin and maybe want to develop Qt programs
> and don't have a real mingw installation (I don't).

  No, there's a mingw mailing list for people who want to develop mingw
programs.  The fact of using a cygwin crosscompiler to build it is no more
relevant than whether you used a cygwin or windows text editor to edit the .C
files.

> PS. I know -mno-cygwin is probably going to be removed in a future
> version of cygwin's compiler, does that mean I would have to maintain a
> real mingw installation to develop Qt programs?

  The plan is to replace it with a real mingw cross-compiler as an optional
package, (and keep the mingw runtime and libs packages, but probably relocate
them into a different part of the cygwin directory tree).  You'll need to
learn to say "i686-pc-mingw-gcc" instead of "gcc -mno-cygwin".

  Remember:  "no-cygwin" means NO CYGWIN.

    cheers,
      DaveK
-- 
Can't think of a witty .sigline today....


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