Unreferenced Libraries?

[JediSpam]

Alright,

I am having a lot of trouble correctly linking libraries to QT 4. I created a simple library called test_class and here is the code:

test_class.cpp
@
#include "test_class.h"

int test_me::whatever(void)
{
return 5;
}
@

test_class.h
@
#ifndef TEST_CLASS_H
#define TEST_CLASS_H

class test_me
{
public:
int whatever(void);
};

#endif
@

I then create that into a .lib and try to call it from my other program in this manner:
@
MainWindow.cpp

test_me abc;
abc.whatever();

@

I have the proper include in MainWindow.cpp and I have the library in my .pro file correct. Any ideas? I'm getting this as an error:

Quoted

mainwindow.cpp:26: error: undefined reference to `test_me::whatever()'
:-1: error: collect2: ld returned 1 exit status

[lgeyer]

Have you added the library to LIBS? Is it properly listed in the linker command when compiling / linking the project?
@
LIBS += -L<path to library> -l<library name>
@

[JediSpam]

Yes i have added the library to my .pro file
@
unix|win32: LIBS += -ltest_code -LC:\VS13_VIEWS\libs
@

just tried the syntax you posted and still no go

[loladiro]

You are not exporting the class.
If you are using Qt Creator, have a look at the library template.

[lgeyer]

[quote author="JediSpam" date="1313071868"]I then create that into a .lib[/quote]

Are we talking about a static library or a shared library?

[JediSpam]

[quote author="Lukas Geyer" date="1313072764"][quote author="JediSpam" date="1313071868"]I then create that into a .lib[/quote]

Are we talking about a static library or a shared library? If so you will have to export symbols as loladiro said.[/quote]

this is a static library i have created in visual studio 2003. i'm trying to understand the library template stuff

[lgeyer]

You might use the nm tool to see which symbols are exported from your library.

[loladiro]

[quote]
this is a static library i have created in visual studio 2003.
[/quote]
Are you trying to mix MSVC and MinGW-compiled code? Not a good Idea!!

[printingesco]

You talking about static library ?

[JediSpam]

[quote author="printingesco" date="1313075382"]You talking about static library ?[/quote]

yes

[JediSpam]

[quote author="loladiro" date="1313072534"]You are not exporting the class.
If you are using Qt Creator, have a look at the library template.[/quote]

I read the qMake Project Files section "Declaring Other Libraries" and don't see what I haven't done correctly.

[quote author="Lukas Geyer" date="1313072949"]You might use the nm tool to see which symbols are exported from your library.[/quote]

Is this a QT tool I don't see it anywhere

[loladiro]

Again, did you compile your library with mingw? It doesn't seem that way because mingw static library files have a .a extension. You cannot mix MSVC and MinGW.

[JediSpam]

[quote author="loladiro" date="1313076573"]Again, did you compile your library with mingw? It doesn't seem that way because mingw static library files have a .a extension. You cannot mix MSVC and MinGW.[/quote]

ah i see. so i'd have to use the MinGW in visual studio to build a library.

[loladiro]

You'd have to either build both the library and app with MinGW or both with MSVC.

[lgeyer]

[quote author="JediSpam" date="1313076335"]
[quote author="Lukas Geyer" date="1313072949"]You might use the nm tool to see which symbols are exported from your library.[/quote]
Is this a QT tool I don't see it anywhere
[/quote]

nm comes with MinGW, which is part of the Qt SDK. Just open a Qt command promt and type nm <binary> to get a list of exported symbols.

(Although it comes with MinGW it should work with any PE - read MSVC - binaries).

[JediSpam]

Thanks for the help guys!