From dc28f2faef12dc5cb260b5707120c024f1b988d5 Mon Sep 17 00:00:00 2001
From: auronandace <auronandace@googlemail.com>
Date: Fri, 8 May 2026 14:59:27 +0100
Subject: [PATCH] split out sizt_t from stddef header

---
 include/stddef.h                            |  3 +-
 src/header/bits_size-t/cbindgen.toml        | 44 +++++++++++++++++++++
 src/header/bits_size-t/mod.rs               |  5 +++
 src/header/mod.rs                           |  6 ++-
 src/header/sys_types_internal/cbindgen.toml |  1 +
 5 files changed, 55 insertions(+), 4 deletions(-)
 create mode 100644 src/header/bits_size-t/cbindgen.toml
 create mode 100644 src/header/bits_size-t/mod.rs

diff --git a/include/stddef.h b/include/stddef.h
index 334267f457..b9c936d26e 100644
--- a/include/stddef.h
+++ b/include/stddef.h
@@ -1,6 +1,7 @@
 #ifndef _STDDEF_H
 #define _STDDEF_H
 #include <stdint.h>
+#include <bits/size-t.h>
 
 #define NULL 0
 
@@ -9,8 +10,6 @@
 #endif
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
 
-typedef long unsigned int size_t;
-
 typedef struct { long long __ll; long double __ld; } max_align_t;
 
 #define offsetof(type, member) __builtin_offsetof(type, member)
diff --git a/src/header/bits_size-t/cbindgen.toml b/src/header/bits_size-t/cbindgen.toml
new file mode 100644
index 0000000000..4fdd282e5d
--- /dev/null
+++ b/src/header/bits_size-t/cbindgen.toml
@@ -0,0 +1,44 @@
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stddef.h.html
+#
+# This type is split out to prevent importing all of stddef.h into other headers.
+#
+# POSIX headers that require size_t:
+# - aio.h
+# - devctl.h (TODO not present in relibc)
+# - dirent.h
+# - glob.h
+# - grp.h
+# - iconv.h (external libiconv (gettext dependency))
+# - monetary.h
+# - mqueue.h (TODO not present in relibc)
+# - nbdm.h (TODO not present in relibc)
+# - pwd.h
+# - regex.h
+# - search.h (TODO not present in relibc)
+# - signal.h
+# - stdio.h
+# - stdlib.h
+# - string.h
+# - strings.h
+# - sys/mman.h
+# - sys/msg.h (TODO not present in relibc)
+# - sys/sem.h (TODO not present in relibc)
+# - sys/shm.h (TODO not present in relibc)
+# - sys/socket.h
+# - sys/types.h (should be re-exported)
+# - sys/uio.h
+# - time.h
+# - uchar.h (TODO not present in relibc)
+# - unistd.h
+# - wchar.h
+# - wordexp.h (TODO not present in relibc)
+sys_includes = []
+include_guard = "_RELIBC_BITS_SIZE_T_H"
+language = "C"
+style = "type"
+no_includes = true
+cpp_compat = true
+[export]
+include = ["size_t"]
+[enum]
+prefix_with_name = true
diff --git a/src/header/bits_size-t/mod.rs b/src/header/bits_size-t/mod.rs
new file mode 100644
index 0000000000..6fefaa468d
--- /dev/null
+++ b/src/header/bits_size-t/mod.rs
@@ -0,0 +1,5 @@
+use crate::platform::types::c_ulong;
+
+/// Unsigned integer type of the result of the sizeof operator.
+#[allow(non_camel_case_types)]
+pub type size_t = c_ulong;
diff --git a/src/header/mod.rs b/src/header/mod.rs
index 9ef9953492..55b7be9ca8 100644
--- a/src/header/mod.rs
+++ b/src/header/mod.rs
@@ -13,6 +13,8 @@ pub mod bits_pthread;
 pub mod bits_safamily_t;
 #[path = "bits_sigset-t/mod.rs"]
 pub mod bits_sigset_t;
+#[path = "bits_size-t/mod.rs"]
+pub mod bits_size_t;
 #[path = "bits_socklen-t/mod.rs"]
 pub mod bits_socklen_t;
 #[path = "bits_ssize-t/mod.rs"]
@@ -23,7 +25,7 @@ pub mod bits_suseconds_t;
 pub mod bits_time_t;
 pub mod bits_timespec;
 pub mod bits_timeval;
-// complex.h implemented in C
+// complex.h implemented in C (currently through openlibm)
 pub mod cpio;
 pub mod crypt;
 pub mod ctype;
@@ -134,7 +136,7 @@ pub mod sys_wait;
 pub mod tar;
 // TODO: term.h (deprecated)
 pub mod termios;
-// TODO: tgmath.h (likely C implementation)
+// TODO: tgmath.h (likely C implementation currenly through openlibm)
 // TODO: threads.h
 pub mod time;
 // TODO: uchar.h
diff --git a/src/header/sys_types_internal/cbindgen.toml b/src/header/sys_types_internal/cbindgen.toml
index 4e253f3ba4..a8862f8ac2 100644
--- a/src/header/sys_types_internal/cbindgen.toml
+++ b/src/header/sys_types_internal/cbindgen.toml
@@ -1,3 +1,4 @@
+# stddef.h brings in size_t
 sys_includes = ["stddef.h"]
 # TODO: figure out how to export void* type
 after_includes = """