newbie question on linking classes

newbie question on linking classes

[Koyel Mukherjee]

Hi

I am a newbie on using gcc and linking files. I have defined some
classes (.h and .cpp files) which I want to use in my main function
defined in a source file(containing the main() function. I have kept
all the class files (.h and .cpp) along with the .cpp source file in
one directory. When I compile only using :
  g++ source.cpp
 it compiles fine. However, when I try to link it too, by writing:
g++ source.cpp -o source_e
I get a series of errors containing
 : undefined reference to func (say) where func is say, a function I
have declared in one of my class files. It seems that it is not able
to link properly . I have included the header files of the classes in
the source file. However I am still getting this error. I tried
specifying the directory where all these files are by the -B option
but it did not help either. Please help me out!

Thanks a lot.

Regards
Koyel

Re: newbie question on linking classes

[John Love-Jensen]

Hi Koyel,

You are compiling and linking source.cpp.

You need to compile and link all your source code.

e.g.
g++ source.cpp uno.cpp dos.cpp tres.cpp -o myapp

If you do your compiling separate from your linking:
g++ source.o uno.o dos.o tres.o -o myapp

HTH,
--Eljay

Re: newbie question on linking classes

[Koyel Mukherjee]

Hi John

Thanks a lot! My code has compiled and linked perfectly now!

Regards
Koyel

On Thu, Mar 27, 2008 at 11:39 AM, John Love-Jensen <eljay@adobe.com> wrote:
> Hi Koyel,
>
>  You are compiling and linking source.cpp.
>
>  You need to compile and link all your source code.
>
>  e.g.
>  g++ source.cpp uno.cpp dos.cpp tres.cpp -o myapp
>
>  If you do your compiling separate from your linking:
>  g++ source.o uno.o dos.o tres.o -o myapp
>
>  HTH,
>  --Eljay
>
>