unistd(3) - NetBSD Manual Pages

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UNISTD(3)               NetBSD 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:

           ·   The implementation-defined NULL pointer constant.

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

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

           ·   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).

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

           ·   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'').

NetBSD 10.0                     August 9, 2011                     NetBSD 10.0