Re: Why does command prompt appear on Windows when starting a GUI app?

[Barry Andrews <titanandrews at earthlink dot net>]

Great! I really appreciate the help. I also did not know about -dumpspecs, so that was also very useful. Thanks!



-----Original Message-----
>From: Brian Dessent <brian@dessent.net>
>Sent: Feb 4, 2006 6:17 PM
>To: Barry Andrews <titanandrews@earthlink.net>
>Cc: gcc-help@gcc.gnu.org
>Subject: Re: Why does command prompt appear on Windows when starting a GUI app?
>
>Barry Andrews wrote:
>
>>    I have a GUI application that is compiled with gcj on Windows.  When I double click the .exe file in Windows Explorer, a command window comes up behind the GUI. Is there any way to get rid of this? Any help is much appreciated!
>
>On win32, when linking a binary there is a field called "subsystem"
>which determines the kind of binary.  This is documented on MSDN:
><http://msdn.microsoft.com/library/en-us/vccore/html/_core_.2f.subsystem.asp>
>
>Just about all normal apps will fall into the "console" or "windows"
>categories, and the only real difference between the two is that a
>console is created for the application by default for the former,
>whereas the application must allocate the console itself (if if even
>needs one) in the latter.
>
>Thus you just need to provide "--subsystem windows" to the linker to set
>this field.  If you are using a compiler driver to link (as you should
>be) instead of calling ld directly then you'll probably have to specify
>this as "-Wl,--subsystem,windows".  The specs file for your compiler may
>have defined "-mwindows" as a shortcut for this; you can check using the
>-dumpspecs flag.
>
>It has been my observation that a lot of people seem to think that
>"-mwindows" is somehow necessary for creating a windows binary, or that
>if they use "-mconsole" they cannot have a GUI.  This is simply not true
>at all -- all this flag does is tell the linker to set the subsystem
>field in the binary to a value which tells the system whether to
>allocate a console by default.  It says nothing about whether the
>application can create graphical windows or anything else.  But it is
>true that often times if an application does have a GUI then it's not
>desirable to have that console window created, so -mwindows sees a lot
>of use in those apps.
>
>Brian