FCHMOD(3P)                                          POSIX Programmer's Manual                                         FCHMOD(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
       fchmod - change mode of a file

SYNOPSIS
       #include <sys/stat.h>

       int fchmod(int fildes, mode_t mode);


DESCRIPTION
       The  fchmod()  function shall be equivalent to chmod() except that the file whose permissions are changed is specified by
       the file descriptor fildes.

       If fildes references a shared memory object, the fchmod() function  need  only  affect  the  S_IRUSR,  S_IWUSR,  S_IRGRP,
       S_IWGRP, S_IROTH, and S_IWOTH file permission bits.

       If fildes references a typed memory object, the behavior of fchmod() is unspecified.

       If fildes refers to a socket, the behavior of fchmod() is unspecified.

       If fildes refers to a STREAM (which is fattach()-ed into the file system name space) the call returns successfully, doing
       nothing.

RETURN VALUE
       Upon successful completion, fchmod() shall return 0. Otherwise, it shall return -1 and set errno to indicate the error.

ERRORS
       The fchmod() function shall fail if:

       EBADF  The fildes argument is not an open file descriptor.

       EPERM  The effective user ID does not match the owner of the file and the process does not have appropriate privilege.

       EROFS  The file referred to by fildes resides on a read-only file system.


       The fchmod() function may fail if:

       EINTR  The fchmod() function was interrupted by a signal.

       EINVAL The value of the mode argument is invalid.

       EINVAL The fildes argument refers to a pipe and the implementation disallows execution of fchmod() on a pipe.


       The following sections are informative.

EXAMPLES
   Changing the Current Permissions for a File
       The following example shows how to change the permissions for a file named /home/cnd/mod1 so that  the  owner  and  group
       have read/write/execute permissions, but the world only has read/write permissions.


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


              mode_t mode;
              int    fildes;
              ...
              fildes = open("/home/cnd/mod1", O_RDWR);
              fchmod(fildes, S_IRWXU | S_IRWXG | S_IROTH | S_IWOTH);

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       chmod(),  chown(), creat(), fcntl(), fstatvfs(), mknod(), open(), read(), stat(), write(), the Base Definitions volume of
       IEEE Std 1003.1-2001, <sys/stat.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                                                    FCHMOD(3P)