FDETACH(3POSIX)

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
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);

APPLICATION USAGE
None.

RATIONALE
None.

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

SEE ALSO
fattach()

The Base Definitions volume of POSIX.1-2017, <stropts.h>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

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 .