glic
The GNU C Library (glibc)
The GNU C Library project provides the core libraries for the GNU system and GNU/Linux systems, as well as many other systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more. The GNU C Library is designed to be a backwards compatible, portable, and high performance ISO C library. It aims to follow all relevant standards including ISO C11, POSIX.1-2008, and IEEE 754-2008. The project was started circa 1988 and is almost 30 years old.
uClibc
A C library for embedded Linux (uClibc)
uClibc (aka µClibc/pronounced yew-see-lib-see) is a C library for developing embedded Linux systems. It is much smaller than the GNU C Library, but nearly all applications supported by glibc also work perfectly with uClibc. Porting applications from glibc to uClibc typically involves just recompiling the source code. uClibc even supports shared libraries and threading. It currently runs on standard Linux and MMU-less (also known as µClinux) systems with support for alpha, amd64, ARM, Blackfin, cris, h8300, hppa, i386, i960, ia64, m68k, mips/mipsel, PowerPC, SH, SPARC, and v850 processors.
EGLIBC
Embedded GLIBC (EGLIBC)
Embedded GLIBC (EGLIBC) was a variant of the GNU C Library (GLIBC) that was designed to work well on embedded systems. EGLIBC strived to be source and binary compatible with GLIBC. EGLIBC's goals included reduced footprint, configurable components, better support for cross-compilation and cross-testing.