Errors while trying to compile with external libraries - c++

Question

I have downloaded the mimetic library installation files,
and followed the INSTALL instructions.
./configure
a script that creates the make file after checking a series of things.
make
compiles the cpp files, after this different .o and .lo files appear in the original folder.
make install
seems to do a lot but the only thing that I seem to notice is that a mimetic directory
appears under /usr/local/include with all the header files.
than I try to compile the most simple main file possible:
(as offered in the library site : original example )
#include <mimetic/mimetic.h>
using namespace mimetic;
int main()
{
MimeEntity me;
return 0;
}
I am compiling with following command ( on CentOS 5.7, gcc version : 4.1.2 ):
g++ mimetic.cpp
The error I get:
/tmp/ccWnsteO.o: In function `main':
mimetic.cpp:(.text+0x80): undefined reference to `mimetic::MimeEntity::MimeEntity()'
mimetic.cpp:(.text+0x91): undefined reference to `mimetic::MimeEntity::~MimeEntity()'
collect2: ld returned 1 exit status
From this I understand that the header files are found but the source/library itself
is missing.
the MimeEntity constructor declaration appears in : /usr/local/include/mimetic/mimeentity.h
when I do a search for mimeentity I get the following :
/home/mimetic-0.9.7/mimetic/mimeentity.o
/home/mimetic-0.9.7/mimetic/mimeentity.h
/home/mimetic-0.9.7/mimetic/mimeentitylist.h
/home/mimetic-0.9.7/mimetic/mimeentity.cxx
/home/mimetic-0.9.7/mimetic/.libs/mimeentity.o
/home/mimetic-0.9.7/mimetic/mimeentity.lo
/home/mimetic-0.9.7/mimetic/.deps/mimeentity.Plo
/usr/local/include/mimetic/mimeentity.h
/usr/local/include/mimetic/mimeentitylist.h
I've tried with a search path to the libraries but the same error appears
g++ mimetic.cpp -L/home/mimetic-0.9.7/mimetic/
Something else strange is happening, when I try to compile the main mimetic.cpp file
with the line
MimeEntity me;
changed to
MimeEntity me();
it compiles.

Answer 1

You are getting a linker error simply because you are not referencing the library when compiling the test source file. It needs to be something like:
g++ mimetic.cpp -l<libraryname>
The reason it compiles when you add the braces is that you are really declaring a function called 'me' that returns a MimeEntry. While it compiles, it does not do what you want.

Answer 2

The command you are using to build your mimetic example seems incomplete. You are specifying library search patch (-L) but not the library itself.
Make sure that -L option specified the location of the mimetic library
Add -l'the-name-of-the-mimetic-library'. My guess would be -lmimetic
Add -I (that is capital i) option for the location of the headers.