This document serves as an overview of HelenOS standard user space API implemented in ''HelenOS C library'' and the relation of this API to common standards such as "C Standard Library" (as defined by various ISO C standards, such as C99) and ''C POSIX Library'' standards.

'''General note:''' The primary aim of ''HelenOS C library'' is not a to be 100% compatible with the standards. For both many fundamental reasons (HelenOS is not an unix-like operating system) and practical reasons (our subjective dislike of some aspects of the standards, security issues, etc.) the ''HelenOS C library'' follows the standards very loosely. Many functions are not implemented because lack of current need or simple because lack of manpower and many functions closely resemble their standard-compliant counterparts, but behave very slightly differently.


== unistd.h ==

|| '''Function''' ||
|| chdir          ||
|| close          ||
|| dup2           ||
|| exit           ||
|| fsync          ||
|| ftruncate      ||
|| getcwd         ||
|| lseek          ||
|| read           ||
|| rmdir          ||
|| sleep          ||
|| unlink         ||
|| usleep         ||
|| write          ||