add armadillo libraries to g++ compiler in linux

Question

I am trying to install a C++ library (armadillo) in a unix cluster where I do not have root permissions.

I managed to compile the C++ libraries without user permissions by running the following make command:

make install DESTDIR=my_usr_dir

But then in the armadillo readme file it says:

where "my_usr_dir" is for storing C++ headers and library files. Make sure your C++ compiler is configured to use the sub-directories present within this directory.

The compiler the armadillo uses to install the libraries is gcc-4.8.1. I am not sure where the compiler was installed but it's loaded when I start my session in the unix cluster.

After installing armadillo I am trying to compile open source code that uses the armadillo libraries. This open source code also has a makefile.

However, when I go to the open source code and I type in:

make 

it calls g++. How can I make sure g++ will recognize the armadillo libraries previously installed in my_usr_dir?

Currently I get the following error if I go to src and then type make:

opencode.cpp:28:21: fatal error: armadillo: No such file or directory
 #include <armadillo>
                     ^
compilation terminated.
make: *** [mmcollapse] Error 1

Answer 1

you can use

 alias gcc="gcc -I./my_usr_dir/include -L./my_usr_dir/lib"

and so on in your .bashrc file. In that way, whenever you invoke gcc on the command line, the flags will be added before every other argument you enter on the command line

Answer 2

I think the readme file refers to the usage of the library headers and library files from applications. For those to be useful, the compiler/linker/loader (usually all driven by the "compiler") have to know where to find them. The compiler always looks in some default directories, such as /usr/include (for headers) and /usr/lib/ (for libraries), but they require root permission to write into. However, you can tell the compiler with the flag -Idirectory to search in directory directory for headers. For libraries use -l and -L (check the manual page of your compiler). You may also need to consider the LD_LIBRARY_PATH and LD_RUN_PATH environment variables, if you're using dynamic linking (shared object files).

Answer 3

This question looks similar to

How to specify non-default shared-library path in GCC Linux? Getting "error while loading shared libraries" when running

If you dont want to change the .bashrc

use -rpath as suggested in the post above.

gcc XXX.c -o xxx.out -Lmy_usr_dir -lXX -Wl,-rpath=my_usr_dir

-L is for static linking -rpath for adding the directory to the linker search path

more on -rpath here

I don't understand -Wl,-rpath -Wl,

Dont bother to upvote the answer because this is really not an answer. I would have commented but i could not locate the add comment for your post.