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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 rou-
	       tines 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 stan-
	       dard.  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

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | STANDARDS

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