erl_global (3erl)

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.

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.

Note:

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.