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Re: CygWin + gcc to build Windows application written in C.
- From: Brian Dessent <brian at dessent dot net>
- To: cygwin at cygwin dot com
- Date: Wed, 14 Dec 2005 17:58:56 -0800
- Subject: Re: CygWin + gcc to build Windows application written in C.
- References: <004a01c600cd$6985cd30$0300a8c0@Piero>
- Reply-to: cygwin at cygwin dot com
Piero Silvestri wrote:
> - I'm looking for some documentation about -mno-cygwin and -mwindows
> options, which I can't find neither in the gcc on-line manual, nor in the
> gcc man pages, nor in the CygWin manual. Where they come from? Using the
> first makes the compiler complain about a missing crt2.o (?), the last seems
> to be ignored.
-mno-cygwin essentially turns gcc into the gcc provided by mingw.org.
Read the docs/wiki/faq/etc at that site for more information. Note that
when you use gcc -mno-cygwin your search paths will be modified so that
no Cygwin libraries/headers will be found, instead the mingw ones will
be searched (/usr/include/mingw, /usr/lib/mingw). Essentially this is
just a shortcut for compiling with the mingw toolchain under Cygwin - do
not get confused and think that this somehow lets you use Cygwin library
functions in any shape or form. If you use mingw or -mno-cygwin, you
are essentially programming directly at the win32 API and the MSVCRT,
you have no unix emulation at all other than what is provided by the
microsoft C library.
-mwindows is a linker option that is short for "--subsystem windows",
just as -mconsole is short for "--subsystem console". You can read more
about ld options at
<http://sourceware.org/binutils/docs-2.16/ld/Options.html>. The actual
meaning of this setting is documented by the Microsoft linker's
This switch probably does not mean what you think it means. It does not
mean "make a windows binary." Nor does it mean "allow the application
to have a GUI." All it does is tell the system not to allocate a
console for the program when it's started.
> - I have a mysterious linker error (undefined reference to __imp___iob); I
> searched the web and found some hints about using MinGW under Cygwin, but
> nothing clear or certain; above all, only questions but not answers...
That probably means that you're trying to mix and match cygwin-compiled
and mingw-compiled objects into a final .exe. That's not going to
work. Cygwin and mingw use completely separate C runtime environments.
They should be considered different platforms completely. You can't
expect to link a Cygwin library into a mingw .exe for example.
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