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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 dif-
       fer (consult 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
       concerning 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 implementa-
       tion-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
              represented 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 struc-
       ture variable buffer is defined for the stat structure. The /home/cnd/mod1 file is opened with read/write priv-
       ileges 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, Stan-
       dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base  Specifica-
       tions  Issue  6,  Copyright (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 Stan-
       dard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .



IEEE/The Open Group                  2003                            FSTAT(3P)