text: /* The <unistd.h> header contains a few miscellaneous manifest constants. */
  
  #ifndef _UNISTD_H
  #define _UNISTD_H
  
  #ifndef _TYPES_H
  #include <minix/types.h>
  #endif
  
  /* Values used by access().  POSIX Table 2-8. */
  #define F_OK               0	/* test if file exists */
  #define X_OK               1	/* test if file is executable */
  #define W_OK               2	/* test if file is writable */
  #define R_OK               4	/* test if file is readable */
  
  /* Values used for whence in lseek(fd, offset, whence).  POSIX Table 2-9. */
  #define SEEK_SET           0	/* offset is absolute  */
  #define SEEK_CUR           1	/* offset is relative to current position */
  #define SEEK_END           2	/* offset is relative to end of file */
  
  /* This value is required by POSIX Table 2-10. */
  #define _POSIX_VERSION 199009L	/* which standard is being conformed to */
  
  /* These three definitions are required by POSIX Sec. 8.2.1.2. */
  #define STDIN_FILENO       0	/* file descriptor for stdin */
  #define STDOUT_FILENO      1	/* file descriptor for stdout */
  #define STDERR_FILENO      2	/* file descriptor for stderr */
  
  #ifdef _MINIX
  /* How to exit the system or stop a server process. */
  #define RBT_HALT	   0	/* shutdown and return to monitor */
  #define RBT_REBOOT	   1	/* reboot the system through the monitor */
  #define RBT_PANIC	   2	/* a server panics */
  #define RBT_MONITOR	   3	/* let the monitor do this */
  #define RBT_RESET	   4	/* hard reset the system */
  #define RBT_INVALID	   5	/* first invalid reboot flag */
  
  #define _PM_SEG_FLAG (1L << 30)	/* for read() and write() to FS by PM */
  #endif
  
  /* What system info to retrieve with sysgetinfo(). */
  #define SI_KINFO	   0	/* get kernel info via PM */
  #define SI_PROC_ADDR	   1	/* address of process table */
  #define SI_PROC_TAB	   2	/* copy of entire process table */
  #define SI_DMAP_TAB	   3	/* get device <-> driver mappings */
  #define SI_MEM_ALLOC	   4	/* get memory allocation data */
  #define SI_DATA_STORE	   5	/* get copy of data store mappings */
  #define SI_SUBSCRIPTION	   6	/* get copy of data store subscriptions */
  #define SI_LOADINFO	   7	/* get copy of load average structure */
  #define SI_KPROC_TAB	   8	/* copy of kernel process table */
  #define SI_CALL_STATS	   9	/* system call statistics */
  #define SI_PCI_INFO	   10	/* get kernel info via PM */
  #define SI_PROCPUB_TAB	   11	/* copy of public entries of process table */
  
  /* NULL must be defined in <unistd.h> according to POSIX Sec. 2.7.1. */
  #define NULL    ((void *)0)
  
  /* The following relate to configurable system variables. POSIX Table 4-2. */
  #define _SC_ARG_MAX	   1
  #define _SC_CHILD_MAX	   2
  #define _SC_CLOCKS_PER_SEC 3
  #define _SC_CLK_TCK	   3
  #define _SC_NGROUPS_MAX	   4
  #define _SC_OPEN_MAX	   5
  #define _SC_JOB_CONTROL	   6
  #define _SC_SAVED_IDS	   7
  #define _SC_VERSION	   8
  #define _SC_STREAM_MAX	   9
  #define _SC_TZNAME_MAX    10
  #define _SC_PAGESIZE	  11
  #define _SC_PAGE_SIZE	  _SC_PAGESIZE
  
  /* The following relate to configurable pathname variables. POSIX Table 5-2. */
  #define _PC_LINK_MAX	   1	/* link count */
  #define _PC_MAX_CANON	   2	/* size of the canonical input queue */
  #define _PC_MAX_INPUT	   3	/* type-ahead buffer size */
  #define _PC_NAME_MAX	   4	/* file name size */
  #define _PC_PATH_MAX	   5	/* pathname size */
  #define _PC_PIPE_BUF	   6	/* pipe size */
  #define _PC_NO_TRUNC	   7	/* treatment of long name components */
  #define _PC_VDISABLE	   8	/* tty disable */
  #define _PC_CHOWN_RESTRICTED 9	/* chown restricted or not */
  
  /* POSIX defines several options that may be implemented or not, at the
   * implementer's whim.  This implementer has made the following choices:
   *
   * _POSIX_JOB_CONTROL	    not defined:	no job control
   * _POSIX_SAVED_IDS 	    not defined:	no saved uid/gid
   * _POSIX_NO_TRUNC	    defined as -1:	long path names are truncated
   * _POSIX_CHOWN_RESTRICTED  defined:		you can't give away files
   * _POSIX_VDISABLE	    defined:		tty functions can be disabled
   */
  #define _POSIX_NO_TRUNC       (-1)
  #define _POSIX_CHOWN_RESTRICTED  1
  
  /* Function Prototypes. */
  _PROTOTYPE( void _exit, (int _status)					);
  _PROTOTYPE( int access, (const char *_path, int _amode)			);
  _PROTOTYPE( unsigned int alarm, (unsigned int _seconds)			);
  _PROTOTYPE( int chdir, (const char *_path)				);
  _PROTOTYPE( int fchdir, (int fd)					);
  _PROTOTYPE( int chown, (const char *_path, uid_t _owner, gid_t _group)	);
  _PROTOTYPE( int fchown, (int fd, uid_t _owner, gid_t _group)	);
  _PROTOTYPE( int close, (int _fd)					);
  _PROTOTYPE( char *ctermid, (char *_s)					);
  _PROTOTYPE( char *cuserid, (char *_s)					);
  _PROTOTYPE( int dup, (int _fd)						);
  _PROTOTYPE( int dup2, (int _fd, int _fd2)				);
  _PROTOTYPE( int execl, (const char *_path, const char *_arg, ...)	);
  _PROTOTYPE( int execle, (const char *_path, const char *_arg, ...)	);
  _PROTOTYPE( int execlp, (const char *_file, const char *arg, ...)	);
  _PROTOTYPE( int execv, (const char *_path, char *const _argv[])		);
  _PROTOTYPE( int execve, (const char *_path, char *const _argv[], 
  						char *const _envp[])	);
  _PROTOTYPE( int execvp, (const char *_file, char *const _argv[])	);
  _PROTOTYPE( pid_t fork, (void)						);
  _PROTOTYPE( long fpathconf, (int _fd, int _name)			);
  _PROTOTYPE( char *getcwd, (char *_buf, size_t _size)			);
  _PROTOTYPE( gid_t getegid, (void)					);
  _PROTOTYPE( uid_t geteuid, (void)					);
  _PROTOTYPE( gid_t getgid, (void)					);
  _PROTOTYPE( int getgroups, (int _gidsetsize, gid_t _grouplist[])	);
  _PROTOTYPE( int setgroups, (int _ngroups, gid_t const *grps)		);
  _PROTOTYPE( char *getlogin, (void)					);
  _PROTOTYPE( pid_t getpgrp, (void)					);
  _PROTOTYPE( pid_t getpid, (void)					);
  _PROTOTYPE( pid_t getppid, (void)					);
  _PROTOTYPE( uid_t getuid, (void)					);
  _PROTOTYPE( int isatty, (int _fd)					);
  _PROTOTYPE( int link, (const char *_existing, const char *_new)		);
  _PROTOTYPE( off_t lseek, (int _fd, off_t _offset, int _whence)		);
  _PROTOTYPE( long pathconf, (const char *_path, int _name)		);
  _PROTOTYPE( int pause, (void)						);
  _PROTOTYPE( int pipe, (int _fildes[2])					);
  _PROTOTYPE( ssize_t read, (int _fd, void *_buf, size_t _n)		);
  _PROTOTYPE( ssize_t pread, (int, void *, size_t, off_t)			);
  _PROTOTYPE( int rmdir, (const char *_path)				);
  _PROTOTYPE( int setgid, (gid_t _gid)				);
  _PROTOTYPE( int setegid, (gid_t _gid)				);
  _PROTOTYPE( pid_t setsid, (void)					);
  _PROTOTYPE( int setuid, (uid_t _uid)				);
  _PROTOTYPE( int seteuid, (uid_t _uid)				);
  _PROTOTYPE( unsigned int sleep, (unsigned int _seconds)			);
  _PROTOTYPE( long sysconf, (int _name)					);
  _PROTOTYPE( pid_t tcgetpgrp, (int _fd)					);
  _PROTOTYPE( int tcsetpgrp, (int _fd, pid_t _pgrp_id)			);
  _PROTOTYPE( char *ttyname, (int _fd)					);
  _PROTOTYPE( int unlink, (const char *_path)				);
  _PROTOTYPE( ssize_t write, (int _fd, const void *_buf, size_t _n)	);
  _PROTOTYPE( int truncate, (const char *_path, off_t _length)		);
  _PROTOTYPE( int ftruncate, (int _fd, off_t _length)			);
  _PROTOTYPE( int nice, (int _incr)					);
  
  /* Open Group Base Specifications Issue 6 (not complete) */
  _PROTOTYPE( int symlink, (const char *path1, const char *path2)		);
  _PROTOTYPE( int readlink, (const char *, char *, size_t)		);
  _PROTOTYPE( int getopt, (int _argc, char * const _argv[], char const *_opts)		);
  extern char *optarg;
  extern int optind, opterr, optopt;
  _PROTOTYPE( int usleep, (useconds_t _useconds)				);
  
  #ifdef _MINIX
  #ifndef _TYPE_H
  #include <minix/type.h>
  #endif
  
  extern int optreset;	/* Reset getopt state */
  
  _PROTOTYPE( int brk, (char *_addr)					);
  _PROTOTYPE( int chroot, (const char *_name)				);
  _PROTOTYPE( int lseek64, (int _fd, u64_t _offset, int _whence,
  						u64_t *_newpos)		);
  _PROTOTYPE( int mknod, (const char *_name, mode_t _mode, dev_t _addr)	);
  _PROTOTYPE( int mknod4, (const char *_name, mode_t _mode, dev_t _addr,
  	    long _size)							);
  _PROTOTYPE( char *mktemp, (char *_template)				);
  _PROTOTYPE( long ptrace, (int _req, pid_t _pid, long _addr, long _data)	);
  _PROTOTYPE( char *sbrk, (int _incr)					);
  _PROTOTYPE( int sync, (void)						);
  _PROTOTYPE( int fsync, (int fd)						);
  _PROTOTYPE( int reboot, (int _how, ...)					);
  _PROTOTYPE( int gethostname, (char *_hostname, size_t _len)		);
  _PROTOTYPE( int getdomainname, (char *_domain, size_t _len)		);
  _PROTOTYPE( int ttyslot, (void)						);
  _PROTOTYPE( int fttyslot, (int _fd)					);
  _PROTOTYPE( char *crypt, (const char *_key, const char *_salt)		);
  _PROTOTYPE( int getsysinfo, (endpoint_t who, int what, void *where)	);
  _PROTOTYPE( int getsigset, (sigset_t *sigset)				);
  _PROTOTYPE( int getprocnr, (void)					);
  _PROTOTYPE( int getnprocnr, (pid_t pid)					);
  _PROTOTYPE( int getpprocnr, (void)					);
  _PROTOTYPE( int _pm_findproc, (char *proc_name, int *proc_nr)		);
  _PROTOTYPE( int mapdriver, (char *label, int major, int style,
  							int flags)	);
  _PROTOTYPE(int adddma, (endpoint_t proc_e,
  				phys_bytes start, phys_bytes size)	);
  _PROTOTYPE(int deldma, (endpoint_t proc_e,
  				phys_bytes start, phys_bytes size)	);
  _PROTOTYPE(int getdma, (endpoint_t *procp, phys_bytes *basep, 
  						phys_bytes *sizep)	);
  
  _PROTOTYPE( pid_t getnpid, (endpoint_t proc_ep)				);
  _PROTOTYPE( uid_t getnuid, (endpoint_t proc_ep)				);
  _PROTOTYPE( gid_t getngid, (endpoint_t proc_ep)				);
  
  /* For compatibility with other Unix systems */
  _PROTOTYPE( int getpagesize, (void)					);
  _PROTOTYPE( int setgroups, (int ngroups, const gid_t *gidset)		);
  _PROTOTYPE( int initgroups, (const char *name, gid_t basegid)		);
  
  #endif
  
  #ifdef _POSIX_SOURCE
  _PROTOTYPE( int getdtablesize, (void)                                   );
  #endif
  
  #endif /* _UNISTD_H */
  