diff --git a/src/header/langinfo/cbindgen.toml b/src/header/langinfo/cbindgen.toml
index 993abcb8ed..d634f47658 100644
--- a/src/header/langinfo/cbindgen.toml
+++ b/src/header/langinfo/cbindgen.toml
@@ -1,6 +1,16 @@
-sys_includes = ["stddef.h", "stdint.h", "features.h"]
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/langinfo.h.html
+#
+# Spec quotations relating to includes:
+# - "The <langinfo.h> header shall define the locale_t type as described in <locale.h>."
+# - "The <langinfo.h> header shall define the nl_item type as described in <nl_types.h>."
+# - "Inclusion of the <langinfo.h> header may also make visible all symbols from <nl_types.h>."
+#
+# TODO move nl_item to nl_types.h (we don't have this header yet) or bits header
 include_guard = "_RELIBC_LANGINFO_H"
-after_includes = "#include <bits/locale-t.h> // locale_t"
+after_includes = """
+#include <bits/locale-t.h> // for locale_t from locale.h
+#include <bits/size-t.h>   // for size_t frome sys/types.h
+"""
 language = "C"
 style = "tag"
 no_includes = true
diff --git a/src/header/langinfo/mod.rs b/src/header/langinfo/mod.rs
index 8f1eb6f81d..f05dba8c59 100644
--- a/src/header/langinfo/mod.rs
+++ b/src/header/langinfo/mod.rs
@@ -4,16 +4,18 @@
 
 // TODO : involve loading locale data. Currently, the implementation only supports the "C" locale.
 
-use crate::header::bits_locale_t::locale_t;
+use crate::{header::bits_locale_t::locale_t, platform::types::size_t};
 use core::ffi::c_char;
 
+// TODO move `nl_item` to nl_types.h (not yet present in relibc) or bits header
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/langinfo.h.html>.
 ///
 /// POSIX type for items used with `nl_langinfo`
-/// In practice, this is an integer index into the string table.
-pub type nl_item = i32;
+/// In practice, this is an index into the string table.
+pub type nl_item = size_t;
 
 // Static string table for langinfo constants
+/// cbindgen:ignore
 static STRING_TABLE: [&[u8]; 81] = [
     b"UTF-8\0",                // CODESET
     b"%a %b %e %H:%M:%S %Y\0", // D_T_FMT
@@ -201,8 +203,8 @@ pub const ABALTMON_12: nl_item = 80;
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn nl_langinfo(item: nl_item) -> *mut c_char {
     // Validate the item and perform the lookup
-    let ptr = if (item as usize) < STRING_TABLE.len() {
-        STRING_TABLE[item as usize].as_ptr().cast::<c_char>()
+    let ptr = if item < STRING_TABLE.len() {
+        STRING_TABLE[item].as_ptr().cast::<c_char>()
     } else {
         // Return a pointer to an empty string if the item is invalid
         c"".as_ptr().cast::<c_char>()
diff --git a/src/header/time/strftime.rs b/src/header/time/strftime.rs
index 5c2ef5f432..90ba34af0f 100644
--- a/src/header/time/strftime.rs
+++ b/src/header/time/strftime.rs
@@ -113,26 +113,26 @@ pub unsafe fn strftime<W: WriteByte>(w: &mut W, format: *const c_char, t: *const
                 // Abbreviated weekday name: %a
                 b'a' => {
                     // `ABDAY_1 + tm_wday` is the correct langinfo ID for abbreviated weekdays
-                    let s = unsafe { langinfo_to_str(ABDAY_1 + (*t).tm_wday) };
+                    let s = unsafe { langinfo_to_str(ABDAY_1 + (*t).tm_wday as usize) };
                     w!(s);
                 }
 
                 // Full weekday name: %A
                 b'A' => {
                     // `DAY_1 + tm_wday` is the correct langinfo ID for full weekdays
-                    let s = unsafe { langinfo_to_str(DAY_1 + (*t).tm_wday) };
+                    let s = unsafe { langinfo_to_str(DAY_1 + (*t).tm_wday as usize) };
                     w!(s);
                 }
 
                 // Abbreviated month name: %b or %h
                 b'b' | b'h' => {
-                    let s = unsafe { langinfo_to_str(ABMON_1 + (*t).tm_mon) };
+                    let s = unsafe { langinfo_to_str(ABMON_1 + (*t).tm_mon as usize) };
                     w!(s);
                 }
 
                 // Full month name: %B
                 b'B' => {
-                    let s = unsafe { langinfo_to_str(MON_1 + (*t).tm_mon) };
+                    let s = unsafe { langinfo_to_str(MON_1 + (*t).tm_mon as usize) };
                     w!(s);
                 }