From 86d63ef27b257583675d8cd515d60c60ee650fe9 Mon Sep 17 00:00:00 2001
From: Alex Orlenko <zxteam@protonmail.com>
Date: Thu, 22 Jan 2026 15:46:31 +0000
Subject: [PATCH] Fix missing BUFSIZ for wasm32 in libc

---
 mlua-sys/src/lua51/lauxlib.rs | 8 ++++++--
 mlua-sys/src/lua52/lauxlib.rs | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/mlua-sys/src/lua51/lauxlib.rs b/mlua-sys/src/lua51/lauxlib.rs
index 2b99083..767d8fe 100644
--- a/mlua-sys/src/lua51/lauxlib.rs
+++ b/mlua-sys/src/lua51/lauxlib.rs
@@ -154,10 +154,14 @@ pub unsafe fn luaL_opt<T>(
 // Generic Buffer Manipulation
 //
 
+#[cfg(target_arch = "wasm32")]
+const BUFSIZ: usize = 1024; // WASI libc's BUFSIZ is 1024
+#[cfg(not(target_arch = "wasm32"))]
+const BUFSIZ: usize = libc::BUFSIZ as usize;
+
 // The buffer size used by the lauxlib buffer system.
 // The "16384" workaround is taken from the LuaJIT source code.
-#[rustfmt::skip]
-pub const LUAL_BUFFERSIZE: usize = if libc::BUFSIZ > 16384 { 8192 } else { libc::BUFSIZ as usize };
+pub const LUAL_BUFFERSIZE: usize = if BUFSIZ > 16384 { 8192 } else { BUFSIZ };
 
 #[repr(C)]
 pub struct luaL_Buffer {
diff --git a/mlua-sys/src/lua52/lauxlib.rs b/mlua-sys/src/lua52/lauxlib.rs
index 635bf92..eb954a4 100644
--- a/mlua-sys/src/lua52/lauxlib.rs
+++ b/mlua-sys/src/lua52/lauxlib.rs
@@ -189,10 +189,14 @@ pub unsafe fn luaL_opt<T>(
 // Generic Buffer Manipulation
 //
 
+#[cfg(target_arch = "wasm32")]
+const BUFSIZ: usize = 1024; // WASI libc's BUFSIZ is 1024
+#[cfg(not(target_arch = "wasm32"))]
+const BUFSIZ: usize = libc::BUFSIZ as usize;
+
 // The buffer size used by the lauxlib buffer system.
 // The "16384" workaround is taken from the LuaJIT source code.
-#[rustfmt::skip]
-pub const LUAL_BUFFERSIZE: usize = if libc::BUFSIZ > 16384 { 8192 } else { libc::BUFSIZ as usize };
+pub const LUAL_BUFFERSIZE: usize = if BUFSIZ > 16384 { 8192 } else { BUFSIZ };
 
 #[repr(C)]
 pub struct luaL_Buffer {