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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 dif-
       fer (consult 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 success-
       fully, 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, 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                           FCHMOD(3P)