1erl_global(3)                 C Library Functions                erl_global(3)
2
3
4

NAME

6       erl_global - Access globally registered names.
7

DESCRIPTION

9   Note:
10       The support for VxWorks is deprecated as of OTP 22, and will be removed
11       in OTP 23.
12
13
14   Note:
15       The old legacy erl_interface library (functions with  prefix  erl_)  is
16       deprecated  as  of OTP 22, and will be removed in OTP 23. This does not
17       apply to the ei library. Reasonably new gcc compilers will issue depre‐
18       cation  warnings.  In order to disable these warnings, define the macro
19       EI_NO_DEPR_WARN.
20
21
22       This module provides support for registering, looking up, and  unregis‐
23       tering  names  in  the  global  module.  For more information, see ker‐
24       nel:global.
25
26       Notice that the functions below perform  an  RPC  using  an  open  file
27       descriptor  provided  by  the  caller. This file descriptor must not be
28       used for other traffic during the global operation, as the function can
29       then receive unexpected data and fail.
30

EXPORTS

32       char **erl_global_names(fd,count)
33
34              Types:
35
36                 int fd;
37                 int *count;
38
39              Retrieves a list of all known global names.
40
41                * fd is an open descriptor to an Erlang connection.
42
43                * count is the address of an integer, or NULL. If count is not
44                  NULL, it is set by the  function  to  the  number  of  names
45                  found.
46
47              On  success, the function returns an array of strings, each con‐
48              taining a single registered name, and sets count to  the  number
49              of  names  found.  The  array  is  terminated  by  a single NULL
50              pointer. On failure, the function returns NULL and count is  not
51              modified.
52
53          Note:
54              It  is the caller's responsibility to free the array afterwards.
55              It has been allocated by the function with a single call to mal‐
56              loc(), so a single free() is all that is necessary.
57
58
59       int erl_global_register(fd,name,pid)
60
61              Types:
62
63                 int fd;
64                 const char *name;
65                 ETERM *pid;
66
67              Registers a name in global.
68
69                * fd is an open descriptor to an Erlang connection.
70
71                * name is the name to register in global.
72
73                * pid  is  the  pid  that  is to be associated with name. This
74                  value is returned by global when processes request the loca‐
75                  tion of name.
76
77              Returns 0 on success, otherwise -1.
78
79       int erl_global_unregister(fd,name)
80
81              Types:
82
83                 int fd;
84                 const char *name;
85
86              Unregisters a name from global.
87
88                * fd is an open descriptor to an Erlang connection.
89
90                * name is the name to unregister from global.
91
92              Returns 0 on success, otherwise -1.
93
94       ETERM *erl_global_whereis(fd,name,node)
95
96              Types:
97
98                 int fd;
99                 const char *name;
100                 char *node;
101
102              Looks up a name in global.
103
104                * fd is an open descriptor to an Erlang connection.
105
106                * name is the name that is to be looked up in global.
107
108              If node is not NULL, it is a pointer to a buffer where the func‐
109              tion can fill in the name of the node where name is found.  node
110              can be passed directly to erl_connect() if necessary.
111
112              On  success,  the  function returns an Erlang pid containing the
113              address of the specified name, and the node  is  initialized  to
114              the  node name where name is found. On failure, NULL is returned
115              and node is not modified.
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119Ericsson AB                   erl_interface 3.13                 erl_global(3)