|FCHMOD(3P)||POSIX Programmer's Manual||FCHMOD(3P)|
PROLOGThis 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.
NAMEfchmod - change mode of a file
DESCRIPTIONThe 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 VALUEUpon successful completion, fchmod() shall return 0. Otherwise, it shall return -1 and set errno to indicate the error.
ERRORSThe fchmod() function shall fail if:
- The fildes argument is not an open file descriptor.
- The effective user ID does not match the owner of the file and the process does not have appropriate privilege.
The file referred to by
fildes resides on a read-only file system.
The fchmod() function may fail if:
- The fchmod() function was interrupted by a signal.
- The value of the mode argument is invalid.
fildes argument refers to a pipe and the implementation disallows execution of
fchmod() on a pipe.
The following sections are informative.
Changing the Current Permissions for a FileThe 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.
fildes = open("/home/cnd/mod1", O_RDWR);
fchmod(fildes, S_IRWXU | S_IRWXG | S_IROTH | S_IWOTH);
SEE ALSOchmod(), chown(), creat(), fcntl(), fstatvfs(), mknod(), open(), read(), stat(), write(), the Base Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h>
COPYRIGHTPortions 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 .
|2003||IEEE/The Open Group|