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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 differ (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 sys-
       tem 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 privileges.
       EROFS  The file referred to by fildes resides on a read-only file  sys-
              tem.
       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 dis-
              allows 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/exe-
       cute 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(),  fstatat(),  fstatvfs(),  mknod(),
       open(), read(), write()
       The Base Definitions volume of POSIX.1-2008, <sys_stat.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  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.unix.org/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.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                           FCHMOD(3P)