fstat(3p) — Linux manual page

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 (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
       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
       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.

       For all other file types defined in this volume of POSIX.1‐2017,
       the structure members st_mode, st_ino, st_dev, st_uid, st_gid,
       st_atim, st_ctim, and st_mtim shall have meaningful values and
       the value of the st_nlink member 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 POSIX.1‐2017, Section
       4.9, 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 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

       fstatat(3p)

       The Base Definitions volume of POSIX.1‐2017, Section 4.9, File
       Times Update, sys_stat.h(0p), sys_types.h(0p)

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                         FSTAT(3P)

Pages that refer to this page: sys_stat.h(0p), fstatat(3p), posix_typed_mem_get_info(3p), posix_typed_mem_open(3p), utime(3p)

---