.TH erl_global 3erl "erl_interface 3.7.18" "Ericsson AB" "C Library Functions"
.SH NAME
erl_global \- Access globally registered names
.SH DESCRIPTION
.LP
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\&.
.LP
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\&.
.SH EXPORTS
.LP
.B
char **erl_global_names(fd,count)
.br
.RS
.LP
Types:

.RS 3
int fd;
.br
int *count;
.br
.RE
.RE
.RS
.LP
Retrieve a list of all known global names\&.
.LP
\fIfd\fR\& is an open descriptor to an Erlang connection\&.
.LP
\fIcount\fR\& is the address of an integer, or NULL\&. If \fIcount\fR\& is not NULL, it will be set by the function to the number of names found\&.
.LP
On success, the function returns an array of strings, each containing a single registered name, and sets \fIcount\fR\& to the number of names found\&. The array is terminated by a single NULL pointer\&. On failure, the function returns NULL and \fIcount\fR\& is not modified\&.
.LP

.RS -4
.B
Note:
.RE
It is the caller\&'s responsibility to free the array afterwards\&. It has been allocated by the function with a single call to \fImalloc()\fR\&, so a single \fIfree()\fR\& is all that is necessary\&.

.RE

.LP
.B
int erl_global_register(fd,name,pid)
.br
.RS
.LP
Types:

.RS 3
int fd;
.br
const char *name;
.br
ETERM *pid;
.br
.RE
.RE
.RS
.LP
This function registers a name in Global\&.
.LP
\fIfd\fR\& is an open descriptor to an Erlang connection\&.
.LP
\fIname\fR\& is the name to register in Global\&.
.LP
\fIpid\fR\& is the pid that should be associated with \fIname\fR\&\&. This is the value that Global will return when processes request the location of \fIname\fR\&\&.
.LP
The function returns 0 on success, or -1 on failure\&.
.RE

.LP
.B
int erl_global_unregister(fd,name)
.br
.RS
.LP
Types:

.RS 3
int fd;
.br
const char *name;
.br
.RE
.RE
.RS
.LP
This function unregisters a name from Global\&.
.LP
\fIfd\fR\& is an open descriptor to an Erlang connection\&.
.LP
\fIname\fR\& is the name to unregister from Global\&.
.LP
The function returns 0 on success, or -1 on failure\&.
.RE

.LP
.B
ETERM *erl_global_whereis(fd,name,node)
.br
.RS
.LP
Types:

.RS 3
int fd;
.br
const char *name;
.br
char *node;
.br
.RE
.RE
.RS
.LP
\fIfd\fR\& is an open descriptor to an Erlang connection\&.
.LP
\fIname\fR\& is the name that is to be looked up in Global\&.
.LP
If \fInode\fR\& is not NULL, it is a pointer to a buffer where the function can fill in the name of the node where \fIname\fR\& is found\&. \fInode\fR\& can be passed directly to \fIerl_connect()\fR\& if necessary\&.
.LP
On success, the function returns an Erlang Pid containing the address of the given name, and node will be initialized to the nodename where \fIname\fR\& is found\&. On failure NULL will be returned and \fInode\fR\& will not be modified\&.
.RE