Meaning of library dl in gcc

Question

I'm checking a makefile, and see that the libraries used are:

LIBS = -lcppunit -ldl

lcppunit is the unit testing library. What is ldl then?

Answer 1

libdl is the dynamic linking library.

Answer 2

This is the interface to the dynamic loader, which provides a client program with ability to do things such as explicitly load other libraries, lookup symbols within, etc.

Most programs do not need to do such things explicitly, since the linker does what is needed to enable ordinary usage of shared libraries while loading the program and libraries themselves. However programs that are clever or try to explore and manipulate the dynamic linking system and its data need explicit access. Some of the capabilities are distantly similar to reflection in Java, though with major limitations (such as applying only to dynamic symbols)

Answer 3

libdl is the dynamic link library used in plugin architectures with well defined interfaces. At least that's how I've seen it used.