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XAddHost() XAddHost()
Name
XAddHost - add a host to the access control list.
Synopsis
XAddHost(display, host)
Display *display;
XHostAddress *host;
Arguments
display Specifies a connection to an X server; returned from XOpenDisplay().
host Specifies the network address of the host machine to be added.
Description
XAddHost() adds the specified host to the access control list for the server specified by display. The access control list is a primitive
security feature that allows access to the server only by other machines listed in a file on the machine running the server. On UNIX-based
systems, this file is called /etc/X?.hosts, where ? is the number of the server.
The application that calls XAddHost() and the server whose list is being updated must be running on the same host machine.
The address data must be a valid address for the type of network in which the server operates, as specified in the family member. Inter-
net, DECnet and ChaosNet networks are currently supported.
For TCP/IP, the address should be in network byte order. For the DECnet family, the server performs no automatic swapping on the address
bytes. A Phase IV address is two bytes long. The first byte contains the least significant eight bits of the node number. The second
byte contains the most significant two bits of the node number in the least significant two bits of the byte, and the area in the most sig-
nificant six bits of the byte.
For more information on access control, see Volume One, Chapter 15, Other Programming Techniques.
Structures
typedef struct {
int family; /* for example FamilyInternet */
int length; /* length of address, in bytes */
char *address; /* pointer to where to find the bytes */
} XHostAddress;
/* The following constants for family member */
#define FamilyInternet 0
#define FamilyDECnet 1
#define FamilyChaos 2
Errors
BadAccess
BadValue
See Also
XAddHosts(), XDisableAccessControl(), XEnableAccessControl(), XListHosts(), XRemoveHost(), XRemoveHosts(), XSetAccessControl().
Xlib - Host Access XAddHost()