Installing software in your home directory: Difference between revisions

{{Command|gcc -o my_prog file1.o file2.o -llapack -lblas}}

if I wanted to link with the LAPACK and BLAS libraries.

The link line needs to contain <tt>-l</tt> prefixed to the library name, which will be a file that has the extension <tt>.a</tt> or <tt>.so</tt>. The documentation for the library will typically inform you of the name of this file and, if there are more than one such file (as may be the case), the order in which they should be linked.

Note that a library [[Using modules | modulefile]] will set environment variables <tt>CPATH</tt> and <tt>LIBRARY_PATH</tt> pointing to the location of the library itself and its include files. These environment variables are supported by most compilers (for example, [https://software.intel.com/en-us/node/522775 Intel] and [https://gcc.gnu.org/onlinedocs/gcc/Environment-Variables.html GCC]), which will automatically try the directories listed in those environment variables during compilation and linking phases. This feature allows you you to easily link against the library without specifying its location explicitly by passing the <tt>-I</tt> and <tt>-L</tt> options to the compiler. If your make- or a config- file calls for an explicit location of the library to pass it to the compiler via those flags, you can safely skip setting those parameters altogether (usually by leaving the location of the library blank in a config file).