Nagios 4 comes with libnagios. It is a C library that provides various functionality that are used in Nagios, and which could also be reused in other programs. This section will talk about the library, how to install it, and how to use it in your programs. If you are not interested in the development of Nagios-related applications in C, you may skip this section.
The functions in the library also make it easier to create software that interact with Nagios, such as plugins, event handlers, or programs that send passive check results. The library is built as a part of the Nagios compilation and is created as a statically linked library only (please visit http://en.wikipedia.org/wiki/Static_library for more details). This means, in order to use the library, it will be included in the application, so we do not have look for it in the shared libraries directory such as /usr/lib.
In order to install the application, go to the source directory of Nagios and run the...