The GNU C Library Reference Manual Version 2.26

<p><strong>You can get a free PDF version of this 1156 page document at gnu.org.  This document is printed in grayscale.</strong></p><p>The C language provides no built-in facilities for performing such common operations as input/output memory management string manipulation and the like. Instead these facilities are defined in a standard library which you compile and link with your programs.</p><p>The GNU C Library described in this document defines all of the library functions that are specified by the ISO C standard as well as additional features specific to POSIX and other derivatives of the Unix operating system and extensions specific to GNU systems.</p><p>The purpose of this manual is to explain how to use the facilities of the GNU C Library. We have mentioned which features belong to which standards to help you identify things that are potentially non-portable to other systems. But the emphasis in this manual is not on strict portability.</p>