netbsd man page for unistd

UNISTD(3)						   BSD Library Functions Manual 						 UNISTD(3)

NAME
     unistd -- standard symbolic constants and types

SYNOPSIS
     #include <unistd.h>

DESCRIPTION
     The <unistd.h> header forms the basis of the Portable Operating System Interface for Unix (POSIX) API.  It includes definitions for numerous
     functions, symbolic constants, and types.	Among these are:

	   o   The implementation-defined NULL pointer constant.

	   o   Types such as size_t, ssize_t, pid_t, and intptr_t.

	   o   Various limits and other symbolic constants described in pathconf(2) and sysconf(3).

	   o   Prototypes for several important system calls and library routines such as chown(2), dup(2), execl(3), fork(2), pipe(2), rmdir(2),
	       setuid(2), and write(2).

	   o   The symbolic constant _POSIX_VERSION that defines the version of the POSIX standard to which the implementation conforms.

	   o   Various other _POSIX -prefixed symbolic constants that indicate whether the system implements some optional part of the standard.
	       Examples include such constants as _POSIX_IPV6 for inet6(4) functionality and _POSIX_ASYNCHRONOUS_IO for aio(3).

SEE ALSO
     limits(3), stddef(3), stdint(3), stdlib(3), types(3)

STANDARDS
     The <unistd.h> header conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

BSD
								  August 9, 2011							       BSD