Looking for good explanation of creation process of Static Lib and it's Test App

SGaist

First thing: are you sure your library is properly statically built on Windows ?

If not, then I would guess you are not properly exporting the symbols from that library hence the missing symbol.

sitesv

@SGaist said in Looking for good explanation of creation process of Static Lib and it's Test App:

First thing: are you sure your library is properly statically built on Windows ?

How I should check this?

SGaist

Are you properly setting the static flag in your library project ? Do you get a .dll when building on Windows ?

sitesv

@SGaist said in Looking for good explanation of creation process of Static Lib and it's Test App:

Are you properly setting the static flag in your library project ? Do you get a .dll when building on Windows ?

Yes. Dll and Lib files are created after building lib.

SGaist

Then your library is not build statically and you are not properly exporting symbols.

For that second part see here.

sitesv

@SGaist thanks. I will recode my lib.

I there any way to debug dynamic/static lib?

SGaist

Sure, use a debug build of your library.

sitesv

@SGaist ones more Q:
But how the same project works in Linux?

SGaist

Because the symbol exportation does not work the same on Linux.

gde23

When you have a library under windows you need to explicitly export the symbols.
On linux it is not necessary because the symbols are managed in another way.

Typically this is done using a preprocessor define that you add at any function / class that you wanna export like (just look it up on stackoverflow)

#ifdef WIN32
    #define DECL_EXPORT __declspec(dllexport)
    #define DECL_IMPORT __declspec(dllimport)
#else
    #define DECL_EXPORT
    #define DECL_IMPORT
#endif

SGaist

@gde23 said in Looking for good explanation of creation process of Static Lib and it's Test App:

When you have a library under windows you need to explicitly export the symbols.
On linux it is not necessary because the symbols are managed in another way.

Typically this is done using a preprocessor define that you add at any function / class that you wanna export like (just look it up on stackoverflow)
#ifdef WIN32
    #define DECL_EXPORT __declspec(dllexport)
    #define DECL_IMPORT __declspec(dllimport)
#else
    #define DECL_EXPORT
    #define DECL_IMPORT
#endif

That is incomplete, The macro to use depend whether you are building the library or using it. See the dedicated chapter in Qt's documentation for a clean way to handle that.

sitesv

@SGaist I checked my code... It is matches to link.
But lib and dll files are created.

Should this code be in pro file:

CONFIG += staticlib

?

So, I have included this string to pro and as a result a lib file only.

Could you please see my test apps? ==> app

gde23

@SGaist You are right. I forgot to mention that part.
@sitesv The dll will be created also if you do not export the symbols. But the exe will not know about the function/class inside the dll so it will not find them.
Did you include the defines as in the description SGaist posted?

sitesv

@gde23 said in Looking for good explanation of creation process of Static Lib and it's Test App:

@SGaist You are right. I forgot to mention that part.
@sitesv The dll will be created also if you do not export the symbols. But the exe will not know about the function/class inside the dll so it will not find them.
Did you include the defines as in the description SGaist posted?

Yes. I checked it. Could you view my code by this link?

UPD: I inserted the line "extern int test();" to main.cpp. And voila!