The_GNU_C_Library_Reference_Manual

The GNU C library, described in this document, denes all of the library functions that are specied by the ISO C standard, as well as additional features specic to POSIX and other derivatives of the Unix operating system, and extensions specic to the GNU system. The purpose of this manual is to tell you how to use the facilities of the GNU 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. strict portability.