Creator and DEF files

[qtYoda]

I'm trying to develop a DLL in Qt Creator. I'm new to Qt and Creator. I'm using windows and vs2010.

I want creator to use a DEF file for the DLL. How can I do that? I added a .def file to the project, it shows up in "Other files" and is apparently not being used.

[squidge]

It isn't used as it serves no purpose.

If you wish to use your DLL in QtCreator, provide the .lib and .dll files so that the dll can be imported into the executable, or just use the .dll file and use dynamic loading (meaning you write the codel to resolve the functions at runtime, rather than the OS doing it at load time). The later also allow you to exit gracefully with a better error message than the OS default.

[qtYoda]

I'm trying to write a DLL with stdcall extern C functions defined (that make use of Qt), but will be used by a non-Qt program.

In VS I was able to use the DEF file to get around the name mangling that goes on with stdcall functions. Like I said, VS just uses the DEF file (at least I don't know where it's specified to the linker), but I can't see how to get Creator to use the def file.

[wysota]

Are you asking about Creator or MinGW?

[qtYoda]

I'm using Creator / VS2010.

[qtYoda]

Maybe I'm attacking this from the wrong angle.

Does Creator produce intermediate make files that are used to compile and link the project via VS2010? If I can get to those I think I can adjust things as I need.

[squidge]

If your using Creator/VS2010, then just modify the linker options for VS2010 to include your DEF file.

Creator supports using whatever compiler you want, but obviously can't support every compiler and linker options those various compilers/linkers can use.

Or you can just do everything in VS2010 and forget about Creator - since your writing the DLL in the VS2010 IDE, you may find it easier to write the application that uses the DLL in that IDE too.

[qtYoda]

If your using Creator/VS2010, then just modify the linker options for VS2010 to include your DEF file.

Creator supports using whatever compiler you want, but obviously can't support every compiler and linker options those various compilers/linkers can use.

Or you can just do everything in VS2010 and forget about Creator - since your writing the DLL in the VS2010 IDE, you may find it easier to write the application that uses the DLL in that IDE too.

I don't want to forget about Creator . But I am new to it and attempting to see if I can use it for my development.

Are you sure Creator doesn't have full control over the VS2010 compiler/linker? That would seem odd to me. The compilers/linkers are generally controllable with command line args--how hard can that be to expose to users? I just need to figure out where/what I need to change to specify the DEF file. Maybe a Creator creator will stop by.

[wysota]

Are you sure Creator doesn't have full control over the VS2010 compiler/linker?

Creator calls qmake which generates a Makefile for the compiler. Forget about Creator, it has nothing to do with your problem, it's just an advanced text editor.

[squidge]

I don't want to forget about Creator . But I am new to it and attempting to see if I can use it for my development.

Why learn something new when you can use something you are already familiar with and know how to use? Qt really doesn't offer anything over VS + Qt plugin.

Are you sure Creator doesn't have full control over the VS2010 compiler/linker?

It is possible, but what I mean is that if you use VS, you can specify many options using the IDE rather than figuring out the correct command line options and altering text files. Therefore I see no advantage of using Qt Creator, all I see is a disadvantage.

[qtYoda]

Why learn something new ...

Really!?

Qt really doesn't offer anything over VS + Qt plugin.

You may, of course, be right. But I'd like to put in some effort to see how much I can do with Creator. I like what i see. I've just run into this DEF file issue and want to see how much is buried, but controllable. I'm just new to it.

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Added after 6 minutes:

Creator calls qmake which generates a Makefile for the compiler. Forget about Creator, it has nothing to do with your problem, it's just an advanced text editor.

Yes, I figured that. But somehow the options that qmake uses must allow control of the build process for the DLL - no? So how does Creator control qmake (options, etc) so you have control of the Makefile from within Creator? I'm mean, you push the little "Run" button and all the magic happens. Something is controlling things from Creator. Can you get in between the steps to control more? Or am I just missing some of the options Creator allows?

[wysota]

But somehow the options that qmake uses must allow control of the build process for the DLL - no?

Yes.

So how does Creator control qmake (options, etc) so you have control of the Makefile from within Creator?

It adds entries to the .pro file but there is no set of checkboxes you can click for advanced control over a particular compiler.

I'm mean, you push the little "Run" button and all the magic happens.

There is no magic. If you push "Run" (or actually "Build"), Creator calls (n)make, that's it. Qt Creator is meant to be a simplistic IDE.

[squidge]

Really!?

Yes, really. Sorry if you like learning new stuff. I rarely get that ability as I code as my main job. Deadlines ensure that if something can be done with existing tools, it will be.

[qtYoda]

Yes.

It adds entries to the .pro file but there is no set of checkboxes you can click for advanced control over a particular compiler.

There is no magic. If you push "Run" (or actually "Build"), Creator calls (n)make, that's it. Qt Creator is meant to be a simplistic IDE.

Got it. Thanks. I'll see if I can modify the makefile to get what I want. Thanks.

[wysota]

Don't modify the makefile. Modify the .pro file.

[qtYoda]

Don't modify the makefile. Modify the .pro file.

Just when I thought I had a solution ...

Here's what I've done so far and thought I'd got it figured out.

1. I found the makefile generated by qmake. In it I found the following linker lines:

$(DESTDIR_TARGET): $(OBJECTS)
$(LINK) $(LFLAGS) /OUT:$(DESTDIR_TARGET) @<<
$(OBJECTS) $(LIBS)

2. I modified these lines to add the /DEF linker option with the def file:

$(DESTDIR_TARGET): $(OBJECTS)
$(LINK) $(LFLAGS) /OUT:$(DESTDIR_TARGET) /DEF:..\dllDialog\dllDialog.def @<<
$(OBJECTS) $(LIBS)

3. This did fix the stdcall name problem and it worked! I also ran clean and rebuilt and the lines stayed in the make file. So it seems only if qmake is rerun will the makefile be regenerated and I'd have to put the /DEF line back in.

So, you suggested modifying the .pro file. How can I modify the .pro file to do the same?

[wysota]

You can modify the QMAKE_LDFLAGS (or was it LFLAGS?) variable.

QMAKE_LDFLAGS+="/DEF ...."

QMAKE_LDFLAGS+="/DEF ...."

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[qtYoda]

You can modify the QMAKE_LDFLAGS (or was it LFLAGS?) variable.

QMAKE_LDFLAGS+="/DEF ...."

QMAKE_LDFLAGS+="/DEF ...."

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Thanks for sticking with this!

I'll check out all the qmake settings. Until now it wasn't needed as I was more exploring the qt gui way of development.

[abrakadobr]

thanks a lot for this topic and answer!
really helped!