Defines implementation characteristics identified by POSIX standard.
/usr/include/unistd.h file includes files that contain
definitions that are required for compatibility with the POSIX standard:
|access.h||Defines symbolic constants for the access subroutine.|
file also defines symbolic constants for the pathconf,
fpathconf, and sysconf subroutines. The
unistd.h file also defines the following symbols, which are
used by POSIX applications to determine implementation characteristics:
|_POSIX_JOB_CONTROL||POSIX-compatible job control is supported.|
|_POSIX_SAVED_IDS||An exec subroutine saves the effective user and group IDs.|
|_POSIX_VERSION||The version of the POSIX standard with which this version of the operating system complies. The value of this symbol is 198808L.|
|_POSIX_CHOWN_RESTRICTED||The use of the chown function is restricted to a process with the appropriate privileges. The group ID of a file can be changed only to the effective group ID or a supplementary group ID of the process. The value of this symbol is -1.|
|_POSIX_VDISABLE||The terminal special characters, which are defined in the termios.h file, can be disabled if this character value is defined by the tcsetattr subroutine. The value of this symbol is -1.|
|_POSIX_NO_TRUNC||Path name components that are longer than NAME_MAX will generate an error.|
file also defines the following symbol, which is used by X/OPEN
|_XOPEN_VERSION||The version of the X/OPEN standard with which this version of the operating system complies.|
This file is provided for POSIX compatibility.
This file is part of Base Operating System (BOS) Runtime.
The limits.h file, sys/types.h file, termios.h file, values.h file.
The access subroutine, exec subroutine.
Header Files Overview.