The Netscape Portable Runtime, or NSPR, is a cross-platform abstraction layer library for the C programming language. It provides a uniform API for various operating system functions.
History
NSPR was originally designed to provide a base for the Java virtual machine in Netscape 5. Over time, it was extended to allow support for additional functionality used for Netscape's server and client software. NSPR continues to be used today by Firefox as well as many of Oracle and Red Hat's server products.
I/O
NSPR provides functions for working with files, directories, anonymous pipes and network sockets.