ei_global(3)

👑 ei_global — the manual page, but make it slay

okay bestie, gather round 💖 this is the ei_global page from erl_interface, and it's lowkey one of the most useful little corner of the Erlang C interface. It's giving "let me talk to the global name registry from C" energy. Let's go. ✨

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🌸 NAME 🌸

ei_global — access globally registered names. that's it, that's the vibe. registering names, looking them up, taking them back. the whole trio. 💅

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🦋 DESCRIPTION 🦋

This module provides support for registering, looking up, and unregistering names in the global module. If you wanna read the main-character lore, go see kernel:global.

🚨 REAL TALK ALERT 🚨 Every single function below does an RPC over an open file descriptor that you (yes, you, bestie) hand it. That fd must not be used for any other traffic while the global operation is happening. If you do? The function can literally receive unexpected data and fail. Not a drill. 😭 Keep that fd sacred. 🔒

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✨ ei_global_names() ✨

char **ei_global_names(ei_cnode *ec, int fd, int *count);

Retrieves a list of all known global names. everything. the whole guest list. 🎀

• ec is the ei_cnode representing the current cnode.
• fd is an open descriptor to an Erlang connection.
• count is the address of an integer, or NULL. If count is not NULL, it is 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. one malloc, one free, that's the deal bestie, slay 🫶

Available since OTP 23.0 ⭐

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🌈 ei_global_register() 🌈

int ei_global_register(int fd, const char *name, erlang_pid *self);

Registers a name in global. claim your throne, queen 👑

• fd is an open descriptor to an Erlang connection.
• name is the name to register in global.
• pid is the pid that is to be associated with name. This value is returned by global when processes request the location of name.

Returns 0 on success, otherwise -1. 🍓

Available since OTP 23.0 ⭐

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💜 ei_global_unregister() 💜

int ei_global_unregister(ei_cnode *ec, int fd, const char *name);

Unregisters a name from global. it's giving... goodbye, no hard feelings, we're not doing this anymore 🙈

• ec is the ei_cnode representing the current cnode.
• fd is an open descriptor to an Erlang connection.
• name is the name to unregister from global.

Returns 0 on success, otherwise -1. 🍓

Available since OTP 23.0 ⭐

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🧚 ei_global_whereis() 🧚

int ei_global_whereis(ei_cnode *ec, int fd, const char *name, erlang_pid* pid, char *node);

Looks up a name in global. where u at, bestie? 📍🔍

• ec is the ei_cnode representing the current cnode.
• fd is an open descriptor to an Erlang connection.
• name is the name that is to be looked up in global.

The pid parameter is a pointer to a erlang_pid that the function will update with the pid associated with the global name, if successful.

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 ei_connect() if necessary. how convenient is that 💅

On success, the function returns 0, updates the erlang_pid pointed to by the pid parameter, and the node parameter is initialized to the node name where name is found. On failure, a negative number is returned. 😭

Available since OTP 23.0 ⭐

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💖 the cute sign-off 💖

and that's the page, bestie!! 🎀 brought to you by Ericsson AB, living in the erl_interface 5.8.2 era, answering to the name ei_global(3). no date printed on this one, so we're just gonna say "timeless ✨". now go free that array. i'm serious. go. 🫶💅🔥