fdetach man page

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.

fdetach — detach a name from a STREAMS-based file descriptor (STREAMS)

Synopsis

#include <stropts.h>

int fdetach(const char *path);

Description

The fdetach() function shall detach a STREAMS-based file from the file to which it was attached by a previous call to fattach(). The path argument points to the pathname of the attached STREAMS file. The process shall have appropriate privileges or be the owner of the file. A successful call to fdetach() shall cause all pathnames that named the attached STREAMS file to again name the file to which the STREAMS file was attached. All subsequent operations on path shall operate on the underlying file and not on the STREAMS file.

All open file descriptions established while the STREAMS file was attached to the file referenced by path shall still refer to the STREAMS file after the fdetach() has taken effect.

If there are no open file descriptors or other references to the STREAMS file, then a successful call to fdetach() shall be equivalent to performing the last close() on the attached file.

Return Value

Upon successful completion, fdetach() shall return 0; otherwise, it shall return -1 and set errno to indicate the error.

Errors

The fdetach() function shall fail if:

EACCES
Search permission is denied on a component of the path prefix.
EINVAL
The path argument names a file that is not currently attached.
ELOOP
A loop exists in symbolic links encountered during resolution of the path argument.
ENAMETOOLONG
The length of a component of a pathname is longer than {NAME_MAX}.
ENOENT
A component of path does not name an existing file or path is an empty string.
ENOTDIR
A component of the path prefix names an existing file that is neither a directory nor a symbolic link to a directory, or the path argument contains at least one non-<slash> character and ends with one or more trailing <slash> characters and the last pathname component names an existing file that is neither a directory nor a symbolic link to a directory.
EPERM
The effective user ID is not the owner of path and the process does not have appropriate privileges.

The fdetach() function may fail if:

ELOOP
More than {SYMLOOP_MAX} symbolic links were encountered during resolution of the path argument.
ENAMETOOLONG
The length of a pathname exceeds {PATH_MAX}, or pathname resolution of a symbolic link produced an intermediate result with a length that exceeds {PATH_MAX}.

The following sections are informative.

Examples

Detaching a File

The following example detaches the STREAMS-based file /tmp/named-STREAM from the file to which it was attached by a previous, successful call to fattach(). Subsequent calls to open this file refer to the underlying file, not to the STREAMS file.

#include <stropts.h>
...
    char *pathname = "/tmp/named-STREAM";
    int ret;

    ret = fdetach(pathname);

Future Directions

The fdetach() function may be removed in a future version.

See Also

fattach()

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

Info

2013 IEEE/The Open Group POSIX Programmer's Manual