XAddHost(3) XLIB FUNCTIONS XAddHost(3)

# [NAME](#NAME)

XAddHost, XAddHosts, XListHosts, XRemoveHost, XRemoveHosts, XSetAccessControl, XEnableAccessControl, XDisableAccessControl, XHostAddress, XServerInterpretedAddress - control host access and host control structure

# [SYNTAX](#SYNTAX)

int XAddHost(Display \**display*, XHostAddress \**host*);

int XAddHosts(Display \**display*, XHostAddress \**hosts*, int *num\_hosts*);

XHostAddress \*XListHosts(Display \**display*, int \**nhosts\_return*, Bool \**state\_return*);

int XRemoveHost(Display \**display*, XHostAddress \**host*);

int XRemoveHosts(Display \**display*, XHostAddress \**hosts*, int *num\_hosts*);

int XSetAccessControl(Display \**display*, int *mode*);

int XEnableAccessControl(Display \**display*);

int XDisableAccessControl(Display \**display*);

# [ARGUMENTS](#ARGUMENTS)

[*display*](#display)

Specifies the connection to the X server.

[*host*](#host)

Specifies the host that is to be added or removed.

[*hosts*](#hosts)

Specifies each host that is to be added or removed.

[*mode*](#mode)

Specifies the mode. You can pass **EnableAccess** or **DisableAccess**.

[*nhosts\_return*](#nhosts_return)

Returns the number of hosts currently in the access control list.

[*num\_hosts*](#num_hosts)

Specifies the number of hosts.

[*state\_return*](#state_return)

Returns the state of the access control.

# [DESCRIPTION](#DESCRIPTION)

The **XAddHost** function adds the specified host to the access control list for that display. The server must be on the same host as the client issuing the command, or a **BadAccess** error results.

**XAddHost** can generate **BadAccess** and **BadValue** errors.

The **XAddHosts** function adds each specified host to the access control list for that display. The server must be on the same host as the client issuing the command, or a **BadAccess** error results.

**XAddHosts** can generate **BadAccess** and **BadValue** errors.

The **XListHosts** function returns the current access control list as well as whether the use of the list at connection setup was enabled or disabled. **XListHosts** allows a program to find out what machines can make connections. It also returns a pointer to a list of host structures that were allocated by the function. When no longer needed, this memory should be freed by calling **XFree**.

The **XRemoveHost** function removes the specified host from the access control list for that display. The server must be on the same host as the client process, or a **BadAccess** error results. If you remove your machine from the access list, you can no longer connect to that server, and this operation cannot be reversed unless you reset the server.

**XRemoveHost** can generate **BadAccess** and **BadValue** errors.

The **XRemoveHosts** function removes each specified host from the access control list for that display. The X server must be on the same host as the client process, or a **BadAccess** error results. If you remove your machine from the access list, you can no longer connect to that server, and this operation cannot be reversed unless you reset the server.

**XRemoveHosts** can generate **BadAccess** and **BadValue** errors.

The **XSetAccessControl** function either enables or disables the use of the access control list at each connection setup.

**XSetAccessControl** can generate **BadAccess** and **BadValue** errors.

The **XEnableAccessControl** function enables the use of the access control list at each connection setup.

**XEnableAccessControl** can generate a **BadAccess** error.

The **XDisableAccessControl** function disables the use of the access control list at each connection setup.

**XDisableAccessControl** can generate a **BadAccess** error.

# [STRUCTURES](#STRUCTURES)

The **XHostAddress** structure contains:

```
typedef struct {


        int family;     /* for example FamilyInternet */


        int length;     /* length of address, in bytes */


        char *address;  /* pointer to where to find the address */
} XHostAddress;
```

The family member specifies which protocol address family to use (for example, TCP/IP or DECnet) and can be **FamilyInternet**, **FamilyInternet6**, **FamilyServerInterpreted**, **FamilyDECnet**, or **FamilyChaos**. The length member specifies the length of the address in bytes. The address member specifies a pointer to the address.

For the ServerInterpreted family, the length is ignored and the address member is a pointer to a **XServerInterpretedAddress** structure which contains:

```
typedef struct {


        int typelength;         /* length of type string, in bytes */


        int valuelength;        /* length of value string, in bytes */


        char *type;             /* pointer to where to find the type string */


        char *value;            /* pointer to where to find the address */
} XServerInterpretedAddress;
```

The type and value members point to strings representing the type and value of the server interpreted entry. These strings may not be NULL-terminated so care should be used when accessing them. The typelength and valuelength members specify the length in byte of the type and value strings.

# [DIAGNOSTICS](#DIAGNOSTICS)

[**BadAccess**](#BadAccess)

A client attempted to modify the access control list from other than the local (or otherwise authorized) host.

[**BadValue**](#BadValue)

Some numeric value falls outside the range of values accepted by the request. Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.

# [SEE ALSO](#SEE_ALSO)

[**XFree**(3)](/man/os/libx11/XFree.3)  
*Xlib - C Language X Interface*

libX11 1.8.14 X Version 11

---

Document: XEnableAccessControl(3) from libx11 1.8.14-r1 (Chainguard OS)
Source: https://gitlab.freedesktop.org/xorg/lib/libx11.git