The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


fattach - attach a STREAMS-based file descriptor to a file in the file system name space


#include <stropts.h>

int fattach(int fildes, const char *path);


The fattach() function attaches a STREAMS-based file descriptor to a file, effectively associating a pathname with fildes. The fildes argument must be a valid open file descriptor associated with a STREAMS file. The path argument points to a pathname of an existing file. The process must have appropriate privileges, or must be the owner of the file named by path and have write permission. A successful call to fattach() causes all pathnames that name the file named by path to name the STREAMS file associated with fildes, until the STREAMS file is detached from the file. A STREAMS file can be attached to more than one file and can have several pathnames associated with it.

The attributes of the named STREAMS file are initialised as follows: the permissions, user ID, group ID, and times are set to those of the file named by path, the number of links is set to 1, and the size and device identifier are set to those of the STREAMS file associated with fildes. If any attributes of the named STREAMS file are subsequently changed (for example, by chmod()), neither the attributes of the underlying file nor the attributes of the STREAMS file to which fildes refers are affected.

File descriptors referring to the underlying file, opened prior to an fattach() call, continue to refer to the underlying file.


Upon successful completion, fattach() returns 0. Otherwise, -1 is returned and errno is set to indicate the error.


The fattach() function will fail if:
Search permission is denied for a component of the path prefix, or the process is the owner of path but does not have write permissions on the file named by path.
The fildes argument is not a valid open file descriptor.
A component of path does not name an existing file or path is an empty string.
A component of the path prefix is not a directory.
The effective user ID of the process is not the owner of the file named by path and the process does not have appropriate privilege.
The file named by path is currently a mount point or has a STREAMS file attached to it.
The size of path exceeds {PATH_MAX}, or a component of path is longer than {NAME_MAX}.
Too many symbolic links were encountered in resolving path.

The fattach() function may fail if:

The fildes argument does not refer to a STREAMS file.
Pathname resolution of a symbolic link produced an intermediate result whose length exceeds {PATH_MAX}.
A link to a file on another file system was attempted.




The fattach() function behaves similarly to the traditional mount() function in the way a file is temporarily replaced by the root directory of the mounted file system. In the case of fattach(), the replaced file need not be a directory and the replacing file is a STREAMS file.




fdetach(), isastream(), <stropts.h>.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
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