FSTAT(3P)                                           POSIX Programmer's Manual                                          FSTAT(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       fstat - get file status

SYNOPSIS
       #include <sys/stat.h>

       int fstat(int fildes, struct stat *buf);


DESCRIPTION
       The  fstat()  function  shall obtain information about an open file associated with the file descriptor fildes, and shall
       write it to the area pointed to by buf.

       If fildes references a shared memory object, the implementation shall update in the stat structure pointed to by the  buf
       argument  only the st_uid, st_gid, st_size, and st_mode fields, and only the S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH,
       and S_IWOTH file permission bits need be valid. The implementation may update other fields and flags.

       If fildes references a typed memory object, the implementation shall update in the stat structure pointed to by  the  buf
       argument  only the st_uid, st_gid, st_size, and st_mode fields, and only the S_IRUSR, S_IWUSR, S_IRGRP, S_IWGRP, S_IROTH,
       and S_IWOTH file permission bits need be valid. The implementation may update other fields and flags.

       The buf argument is a pointer to a stat structure, as defined in <sys/stat.h>, into which information is placed  concern-
       ing the file.

       The  structure  members  st_mode,  st_ino, st_dev, st_uid, st_gid, st_atime, st_ctime, and st_mtime shall have meaningful
       values for all other file types defined in this volume of IEEE Std 1003.1-2001. The value of the member st_nlink shall be
       set to the number of links to the file.

       An  implementation  that  provides  additional  or  alternative file access control mechanisms may, under implementation-
       defined conditions, cause fstat() to fail.

       The  fstat()  function  shall  update  any  time-related  fields  as  described  in  the  Base  Definitions   volume   of
       IEEE Std 1003.1-2001, Section 4.7, File Times Update, before writing into the stat structure.

RETURN VALUE
       Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and errno set to indicate the error.

ERRORS
       The fstat() function shall fail if:

       EBADF  The fildes argument is not a valid file descriptor.

       EIO    An I/O error occurred while reading from the file system.

       EOVERFLOW
              The  file  size  in bytes or the number of blocks allocated to the file or the file serial number cannot be repre-
              sented correctly in the structure pointed to by buf.


       The fstat() function may fail if:

       EOVERFLOW
              One of the values is too large to store into the structure pointed to by the buf argument.


       The following sections are informative.

EXAMPLES
   Obtaining File Status Information
       The following example shows how to obtain file status information for a file named /home/cnd/mod1. The structure variable
       buffer  is  defined for the stat structure. The /home/cnd/mod1 file is opened with read/write privileges and is passed to
       the open file descriptor fildes.


              #include <sys/types.h>
              #include <sys/stat.h>
              #include <fcntl.h>


              struct stat buffer;
              int         status;
              ...
              fildes = open("/home/cnd/mod1", O_RDWR);
              status = fstat(fildes, &buffer);

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       lstat(), stat(), the Base Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h>, <sys/types.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                     FSTAT(3P)