The fchmod() function shall be equivalent to chmod() except that
the file whose permissions are changed is specified by the file descriptor
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
If fildes refers to a STREAM (which is fattach()-ed into the file
system name space) the call returns successfully, doing nothing.
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.
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, 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 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