[LINUX] Shared Library Files, Qt, Eu, and open_dll()
Hello everyone!
I am currently working on a window toolkit for Euphoria using Qt. One of the
main sticking points in all of this is that the shared libraries for Qt were
written and compiled for C++, which creates a great deal of difficulty since
it is, of course, object oriented, and since gcc mangles all the function
names.
To get around this, I've been writing my own shared library for use with my
toolkit. The shared library that I am writing works with the C++ code, but
provides C functions ... these functions are declared using extern "C", which
means that gcc will not mangle the function names. (I've verified the fact
that it *isn't* mangling them.)
At any rate, I had the toolkit working well enough to successfully write
Tutorial #1 in the Qt documentation using Euphoria. I then decided to make
an error window class, and place that into the library. Once I did that,
Euphoria could no longer open the shared library, and open_dll() returned a
value of -1.
Using two different makefiles, I've been able to toggle the library, compiling
the error window code into the .so file, and then clean making it with the
other makefile, which leaves that code out. When the error window code is
left out, Euphoria opens the .so without a problem. When it is included,
Euphoria cannot open it.
Since Euphoria's inability to open the shared library only occurs when that
code is included, I suspect that the problem lies in my C++ code, or some
quirk with Linux that I'm unfamiliar with. I had also considered that
perhaps that code was causing another library to be loaded which could be
causing the problem; however, in both the "works" and "don't works" case, I'm
still linking to the same libraries, libqt.so and libqui.so.
The only other two significant changes I can think of are:
1. The code for the base class for my error window (which is derived from
QDialog), is being generated by the Qt tool uic. [This is because I've
designed it using the Qt-Designer.] It also uses the moc tool, but this
isn't significant, because moc is also run on some of the other header files
in the "works" version.
2. The suspect code is also the only code in the library (thus far) that
makes use of Qt's signal/slot event handling system.
Why either of these facts would be an issue with Euphoria not opening the
shared library file escapes me. Nothing has changed in the linking process,
and none of the options that I've used to build the library (using gcc) have
changed. And finally, gcc is not issuing any errors or warnings when making
the .so file. I've even tried running ldconfig -n ., without effect.
Any thoughts?
Have a good morning/day/afternoon/evening/night,
Travis W. Beaty
Osage, Iowa.
--
You'll never see all the places, or read all the books, but fortunately,
they're not all recommended.
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