File 0165-references-erl_nif-clear-up-NULL-NUL-confusion.patch of Package erlang
From 8ea2346b05493a988db98d9126e1b4fff18a039e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=BD=D0=B0=D0=B1?= <nabijaczleweli@nabijaczleweli.xyz>
Date: Wed, 10 Dec 2025 18:53:28 +0100
Subject: [PATCH] references/erl_nif: clear up `NULL`/NUL confusion
NULL is a C macro (thus, ``) that evaluates to a null pointer literal.
NUL is what ASCII calls the 0 byte.
C strings consist of bytes (not characters),
especially when you have non-single-byte encodings.
---
erts/doc/references/erl_nif.md | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/erts/doc/references/erl_nif.md b/erts/doc/references/erl_nif.md
index 6f3e81aae3..90d689b5af 100644
--- a/erts/doc/references/erl_nif.md
+++ b/erts/doc/references/erl_nif.md
@@ -1304,11 +1304,11 @@ int enif_get_atom(
ErlNifCharEncoding encoding);
```
-Writes a `NULL`\-terminated string in the buffer pointed to by `buf` of size
+Writes a NUL\-terminated string in the buffer pointed to by `buf` of size
`size` bytes, consisting of the string representation of the atom `term` with
[encoding](erl_nif.md#ErlNifCharEncoding).
-Returns the number of bytes written (including terminating `NULL` character) or
+Returns the number of bytes written (including terminating NUL byte), or
`0` if `term` is not an atom with maximum length of `size-1` bytes in
`encoding`.
@@ -1324,8 +1324,8 @@ int enif_get_atom_length(
ErlNifCharEncoding encoding);
```
-Sets `*len` to the length (number of bytes excluding terminating `NULL`
-character) of the atom `term` with [encoding](erl_nif.md#ErlNifCharEncoding).
+Sets `*len` to the length (number of bytes excluding terminating NUL
+byte) of the atom `term` with [encoding](erl_nif.md#ErlNifCharEncoding).
Returns `true` on success, or `false` if `term` is not an atom or if the atom
cannot be encoded using `encoding`.
@@ -1521,18 +1521,18 @@ int enif_get_string(
ErlNifCharEncoding encoding);
```
-Writes a `NULL`\-terminated string in the buffer pointed to by `buf` with size
+Writes a NUL\-terminated string in the buffer pointed to by `buf` with size
`size`, consisting of the characters in the string `list`. The characters are
written using [encoding](erl_nif.md#ErlNifCharEncoding).
Returns one of the following:
-- The number of bytes written (including terminating `NULL` character)
+- The number of bytes written (including the terminating NUL byte)
- `-size` if the string was truncated because of buffer space
- `0` if `list` is not a string that can be encoded with `encoding` or if `size`
was < `1`.
-The written string is always `NULL`\-terminated, unless buffer `size` is < `1`.
+The written string is always NUL\-terminated, unless buffer `size` is `0`.
Available since OTP R13B04
@@ -1546,8 +1546,8 @@ int enif_get_string_length(
ErlNifCharEncoding encoding);
```
-Sets `*len` to the length (number of bytes excluding terminating `NULL`
-character) of the string `list` with [encoding](erl_nif.md#ErlNifCharEncoding).
+Sets `*len` to the length (number of bytes excluding terminating NUL
+byte) of the string `list` with [encoding](erl_nif.md#ErlNifCharEncoding).
Returns `true` on success, or `false` if `list` is not a string that can be
encoded with `encoding`.
@@ -2101,7 +2101,7 @@ ERL_NIF_TERM enif_make_atom(
const char *name);
```
-Creates an atom term from the `NULL`\-terminated C-string `name` with ISO
+Creates an atom term from the NUL\-terminated C-string `name` with ISO
Latin-1 encoding. If the length of `name` exceeds the maximum length allowed for
an atom (255 characters), `enif_make_atom` invokes
[`enif_make_badarg`](erl_nif.md#enif_make_badarg).
@@ -2116,7 +2116,7 @@ ERL_NIF_TERM enif_make_atom_len(
```
Create an atom term from the string `name` with length `len` and ISO Latin-1
-encoding. `NULL` characters are treated as any other characters. If `len`
+encoding. `NUL` bytes are treated as any other characters. If `len`
exceeds the maximum length allowed for an atom (255 characters),
`enif_make_atom` invokes [`enif_make_badarg` ](erl_nif.md#enif_make_badarg).
@@ -2198,7 +2198,7 @@ int enif_make_existing_atom(
ErlNifCharEncoding encoding);
```
-Tries to create the term of an already existing atom from the `NULL`\-terminated
+Tries to create the term of an already existing atom from the NUL\-terminated
C-string `name` with [encoding](erl_nif.md#ErlNifCharEncoding).
If the atom already exists, this function stores the term in `*atom` and returns
@@ -2220,8 +2220,8 @@ int enif_make_existing_atom_len(
```
Tries to create the term of an already existing atom from the string `name` with
-length `len` bytes and [encoding](erl_nif.md#ErlNifCharEncoding). `NULL`
-characters are treated as any other characters.
+length `len` bytes and [encoding](erl_nif.md#ErlNifCharEncoding). `NUL`
+bytes are treated as any other characters.
If the atom already exists, this function stores the term in `*atom` and returns
`true`, otherwise returns `false`. It also returns `false` if the string `name`
@@ -2489,7 +2489,7 @@ int enif_make_new_atom(
ErlNifCharEncoding encoding);
```
-Creates an atom term from the `NULL`\-terminated C-string `name` with
+Creates an atom term from the NUL\-terminated C-string `name` with
[encoding](erl_nif.md#ErlNifCharEncoding).
If successful, `true` is returned and the atom term is stored in `*atom`.
@@ -2674,7 +2674,7 @@ ERL_NIF_TERM enif_make_string(
ErlNifCharEncoding encoding);
```
-Creates a list containing the characters of the `NULL`\-terminated string
+Creates a list containing the characters of the NUL\-terminated string
`string` with [encoding](erl_nif.md#ErlNifCharEncoding).
## enif_make_string_len()
@@ -2688,7 +2688,7 @@ ERL_NIF_TERM enif_make_string_len(
```
Creates a list containing the characters of the string `string` with length
-`len` and [encoding](erl_nif.md#ErlNifCharEncoding). `NULL` characters are
+`len` and [encoding](erl_nif.md#ErlNifCharEncoding). NUL bytes are
treated as any other characters.
Available since OTP R14B
--
2.51.0
