shared library problem

[nhatkhang]

hi !
i'm using Kdevelop 3.3.1(Using KDE 3.5.1-2.3 Red Hat).
i have 2 files demo.c and BkTransLib.h, 1 shared library libbktrans.so.0.0

// demo.c
#include "BkTransLib.h"
int main() {

if (BKInit()) printf("Start BkTransLib ok\n");
else {
printf("Start BkTransLib Fail\n");
return 0;
}
}

//"BkTransLib.h"
int BKInit();

and libbktrans.so.0.0 is a shared library contains function BKInit()

i put libbktrans.so.0.0 in /usr/local/lib, make two links here
ln -sf libbktrans.so.0.0 libbktrans.so.0
ln -sf libbktrans.so.0 libbktrans.so
now i create a C project with Automake Manager, add the two files into it and build the project. Of course, i get an error: "undefined reference to BKInit()".it's because i haven't not added my shared library into the project.
To fix this, i open Automake Manager and select the project line, right-click and select Options from the drop menu. Choose the Library tab, in the second box("Link library outside project(LDADD)"), add -lbktrans.

rebuild the project -->Success
execute program, i get
Start BkTransLib ok
Press Enter to continue!
well, perfect !

Now i modify demo.c to create demo.cpp
//demo.cpp
#include "BkTransLib.h"
#include <qwhatsthis.h>

int main() {

if (BKInit()) qWarning( "Start BkTransLib ok\n" );
else {
qWarning("Start BkTransLib Fail\n");
return 0;
}
}
then i create a C++ project (C++ --> KDE --> Simple KDE Application), add demo.cpp and BkTransLib.h into it. Once again i get the error "undefined reference...". so i do the same as the C project. unluckily, the error does not disappear.

i don't know why, i even follow the direction of FAQ at http://www.kdevelop.org/mediawiki/in....so_library.3F
1. add -lbktrans in "link libraries outside of project" like above
2. add -L/usr/local/lib to the LDFLAGS in Project->Project Options...->Configure Options->Linker Flags(LDFLAGS)
3. add -I/usr/local/lib to the "Directories outside of project" in the tab Include
rebuild but nothing changes.

Please tell me what.

Thank you.

[jacek]

1. add -lbktrans in "link libraries outside of project" like above
2. add -L/usr/local/lib to the LDFLAGS in Project->Project Options...->Configure

Try adding "-L/usr/local/lib -lbktrans" to "link libraries outside of project", make sure that /usr/local/lib is in /etc/ld.so.conf and rerun ldconfig.

[nhatkhang]

hi
i tried, but nothing changed

perhaps, the shared library libbktrans.so can't link into a C++ project.(this is my very stupid idea !)
because i was successful to link against a simple shared library to both C and C++ project.
does anyone have a better idea ?
Regards
nhatkhang

[jacek]

because i was successful to link against a simple shared library to both C and C++ project.

But was it libbktrans.so or some other library? Maybe you forgot to add extern "C"?

[nhatkhang]

hi
i only built successfully with libbktrans.so on C project, but not C++ project

i followed the directions and example at http://tldp.org/HOWTO/Program-Librar...-examples.html to make a simple shared library, and i could handle both C and C++ project.

[jacek]

i followed the directions and example at http://tldp.org/HOWTO/Program-Librar...-examples.html to make a simple shared library,

I hope you didn't forgot about section 5.8. from that howto.

[nhatkhang]

hi !
i got the solution. you're the number one
thank you

nhatkhang