bionic (3) fchmod.3posix.gz

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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 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 privileges.

       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(), fstatat(), fstatvfs(), mknod(), open(), read(), write()

       The Base Definitions volume of POSIX.1‐2008, <sys_stat.h>


       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 Electrical 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.kernel.org/doc/man-pages/reporting_bugs.html .