(libc.info.gz) Local Namespace Concepts

Info Catalog

(libc.info.gz) Local Namespace

(libc.info.gz) Local Namespace Details

 
 16.5.1 Local Namespace Concepts
 -------------------------------
 
 In the local namespace socket addresses are file names.  You can specify
 any file name you want as the address of the socket, but you must have
 write permission on the directory containing it.  It's common to put
 these files in the '/tmp' directory.
 
    One peculiarity of the local namespace is that the name is only used
 when opening the connection; once open the address is not meaningful and
 may not exist.
 
    Another peculiarity is that you cannot connect to such a socket from
 another machine-not even if the other machine shares the file system
 which contains the name of the socket.  You can see the socket in a
 directory listing, but connecting to it never succeeds.  Some programs
 take advantage of this, such as by asking the client to send its own
 process ID, and using the process IDs to distinguish between clients.
 However, we recommend you not use this method in protocols you design,
 as we might someday permit connections from other machines that mount
 the same file systems.  Instead, send each new client an identifying
 number if you want it to have one.
 
    After you close a socket in the local namespace, you should delete
 the file name from the file system.  Use 'unlink' or 'remove' to do
 this; see  Deleting Files.
 
    The local namespace supports just one protocol for any communication
 style; it is protocol number '0'.
 

Info Catalog

(libc.info.gz) Local Namespace

(libc.info.gz) Local Namespace Details