Re: [OATH-Toolkit-help] compilation problem using liboath library

[Ilkka Virta]

On 27.5.2013 1:19, Alan Markus wrote:
> Hi,
>
> I am trying to use the oath-toolkit lib to test totp but i am having a
> problem when i try to compile my "test" program with the liboath
> library. Sorry for asking this here but i am sutcked for the last 2 days.
>
> here is the information:
> Library is installed from oath-toolkit source, compilation and
> installation without problems.
> address@hidden:~/totp$ sudo ldconfig -v | grep liboath
> liboath.so.0 -> liboath.so.0.1.3
>
> My main.cpp "test" program:
> #include <liboath/oath.h>

> address@hidden:~/totp$ g++ main.cpp -loath -o teste
> /tmp/ccXbve8u.o: In function `main':
> main.cpp:(.text+0x45): undefined reference to `oath_init()'

Since that's a C program (instead of C++), you should use gcc to compile 
it instead of g++.

If you change to C++ at some point, and use a C library (like -loath), 
you have wrap the C declarations (or the header file) in extern "C" {}.
This should work:

extern "C" {
#include <liboath/oath.h>
}

You should find more information on this online (way more than I 
know..., see for example:
http://stackoverflow.com/questions/1041866/in-c-source-what-is-the-effect-of-extern-c


--
Ilkka Virta / itvirta at iki.fi