# erl_global

### C LIBRARY

erl_global

### C LIBRARY SUMMARY

Access globally registered names

### DESCRIPTION

This module provides support for registering, looking up and unregistering names in the Erlang Global module. For more information, see the description of Global in the reference manual.

Note that the functions below perform an RPC using an open file descriptor provided by the caller. This file descriptor must not be used for other traffic during the global operation or the function may receive unexpected data and fail.

### EXPORTS

`char **erl_global_names(fd,count)`

Types:

`int fd;`
`int *count;`

Retrieve a list of all known global names.

`fd` is an open descriptor to an Erlang connection.

`count` is the address of an integer, or NULL. If `count` is not NULL, it will be set by the function to the number of names found.

On success, the function returns an array of strings, each containing a single registered name, and sets `count` to the number of names found. The array is terminated by a single NULL pointer. On failure, the function returns NULL and `count` is not modified.

| It is the caller's responsibility to free the array afterwards. It has been allocated by the function with a single call to `malloc()`, so a single `free()` is all that is necessary.

`int erl_global_register(fd,name,pid)`

Types:

`int fd;`
`const char *name;`
`ETERM *pid;`

This function registers a name in Global.

`fd` is an open descriptor to an Erlang connection.

`name` is the name to register in Global.

`pid` is the pid that should be associated with `name`. This is the value that Global will return when processes request the location of `name`.

The function returns 0 on success, or -1 on failure.

`int erl_global_unregister(fd,name)`

Types:

`int fd;`
`const char *name;`

This function unregisters a name from Global.

`fd` is an open descriptor to an Erlang connection.

`name` is the name to unregister from Global.

The function returns 0 on success, or -1 on failure.

`ETERM *erl_global_whereis(fd,name,node)`

Types:

`int fd;`
`const char *name;`
`char *node;`

`fd` is an open descriptor to an Erlang connection.

`name` is the name that is to be looked up in Global.

If `node` is not NULL, it is a pointer to a buffer where the function can fill in the name of the node where `name` is found. `node` can be passed directly to `erl_connect()` if necessary.

On success, the function returns an Erlang Pid containing the address of the given name, and node will be initialized to the nodename where `name` is found. On failure NULL will be returned and `node` will not be modified.

### AUTHORS

Gordon Beaton - support@erlang.ericsson.se

erl_interface 3.5.5.3
Copyright © 1991-2007 Ericsson AB