diff --git a/mlua-sys/src/lua51/lualib.rs b/mlua-sys/src/lua51/lualib.rs
index de994ce..9ef0b21 100644
--- a/mlua-sys/src/lua51/lualib.rs
+++ b/mlua-sys/src/lua51/lualib.rs
@@ -1,24 +1,24 @@
 //! Contains definitions from `lualib.h`.
 
-use std::os::raw::{c_char, c_int};
+use std::os::raw::c_int;
 
 use super::lua::lua_State;
 
-pub const LUA_COLIBNAME: *const c_char = cstr!("coroutine");
-pub const LUA_TABLIBNAME: *const c_char = cstr!("table");
-pub const LUA_IOLIBNAME: *const c_char = cstr!("io");
-pub const LUA_OSLIBNAME: *const c_char = cstr!("os");
-pub const LUA_STRLIBNAME: *const c_char = cstr!("string");
-pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
-pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
-pub const LUA_LOADLIBNAME: *const c_char = cstr!("package");
+pub const LUA_COLIBNAME: &str = "coroutine";
+pub const LUA_TABLIBNAME: &str = "table";
+pub const LUA_IOLIBNAME: &str = "io";
+pub const LUA_OSLIBNAME: &str = "os";
+pub const LUA_STRLIBNAME: &str = "string";
+pub const LUA_MATHLIBNAME: &str = "math";
+pub const LUA_DBLIBNAME: &str = "debug";
+pub const LUA_LOADLIBNAME: &str = "package";
 
 #[cfg(feature = "luajit")]
-pub const LUA_BITLIBNAME: *const c_char = cstr!("bit");
+pub const LUA_BITLIBNAME: &str = "bit";
 #[cfg(feature = "luajit")]
-pub const LUA_JITLIBNAME: *const c_char = cstr!("jit");
+pub const LUA_JITLIBNAME: &str = "jit";
 #[cfg(feature = "luajit")]
-pub const LUA_FFILIBNAME: *const c_char = cstr!("ffi");
+pub const LUA_FFILIBNAME: &str = "ffi";
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua51", kind = "raw-dylib"))]
 extern "C-unwind" {
diff --git a/mlua-sys/src/lua52/lualib.rs b/mlua-sys/src/lua52/lualib.rs
index a9ed21f..daf1e2a 100644
--- a/mlua-sys/src/lua52/lualib.rs
+++ b/mlua-sys/src/lua52/lualib.rs
@@ -1,18 +1,18 @@
 //! Contains definitions from `lualib.h`.
 
-use std::os::raw::{c_char, c_int};
+use std::os::raw::c_int;
 
 use super::lua::lua_State;
 
-pub const LUA_COLIBNAME: *const c_char = cstr!("coroutine");
-pub const LUA_TABLIBNAME: *const c_char = cstr!("table");
-pub const LUA_IOLIBNAME: *const c_char = cstr!("io");
-pub const LUA_OSLIBNAME: *const c_char = cstr!("os");
-pub const LUA_STRLIBNAME: *const c_char = cstr!("string");
-pub const LUA_BITLIBNAME: *const c_char = cstr!("bit32");
-pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
-pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
-pub const LUA_LOADLIBNAME: *const c_char = cstr!("package");
+pub const LUA_COLIBNAME: &str = "coroutine";
+pub const LUA_TABLIBNAME: &str = "table";
+pub const LUA_IOLIBNAME: &str = "io";
+pub const LUA_OSLIBNAME: &str = "os";
+pub const LUA_STRLIBNAME: &str = "string";
+pub const LUA_BITLIBNAME: &str = "bit32";
+pub const LUA_MATHLIBNAME: &str = "math";
+pub const LUA_DBLIBNAME: &str = "debug";
+pub const LUA_LOADLIBNAME: &str = "package";
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua52", kind = "raw-dylib"))]
 extern "C-unwind" {
diff --git a/mlua-sys/src/lua53/lauxlib.rs b/mlua-sys/src/lua53/lauxlib.rs
index 53c45bd..7c851ac 100644
--- a/mlua-sys/src/lua53/lauxlib.rs
+++ b/mlua-sys/src/lua53/lauxlib.rs
@@ -9,10 +9,10 @@ use super::lua::{self, lua_CFunction, lua_Integer, lua_Number, lua_State};
 pub const LUA_ERRFILE: c_int = lua::LUA_ERRERR + 1;
 
 // Key, in the registry, for table of loaded modules
-pub const LUA_LOADED_TABLE: *const c_char = cstr!("_LOADED");
+pub const LUA_LOADED_TABLE: &str = "_LOADED";
 
 // Key, in the registry, for table of preloaded loaders
-pub const LUA_PRELOAD_TABLE: *const c_char = cstr!("_PRELOAD");
+pub const LUA_PRELOAD_TABLE: &str = "_PRELOAD";
 
 #[repr(C)]
 pub struct luaL_Reg {
diff --git a/mlua-sys/src/lua53/lualib.rs b/mlua-sys/src/lua53/lualib.rs
index 0b556d4..5d7509e 100644
--- a/mlua-sys/src/lua53/lualib.rs
+++ b/mlua-sys/src/lua53/lualib.rs
@@ -1,19 +1,19 @@
 //! Contains definitions from `lualib.h`.
 
-use std::os::raw::{c_char, c_int};
+use std::os::raw::c_int;
 
 use super::lua::lua_State;
 
-pub const LUA_COLIBNAME: *const c_char = cstr!("coroutine");
-pub const LUA_TABLIBNAME: *const c_char = cstr!("table");
-pub const LUA_IOLIBNAME: *const c_char = cstr!("io");
-pub const LUA_OSLIBNAME: *const c_char = cstr!("os");
-pub const LUA_STRLIBNAME: *const c_char = cstr!("string");
-pub const LUA_UTF8LIBNAME: *const c_char = cstr!("utf8");
-pub const LUA_BITLIBNAME: *const c_char = cstr!("bit32");
-pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
-pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
-pub const LUA_LOADLIBNAME: *const c_char = cstr!("package");
+pub const LUA_COLIBNAME: &str = "coroutine";
+pub const LUA_TABLIBNAME: &str = "table";
+pub const LUA_IOLIBNAME: &str = "io";
+pub const LUA_OSLIBNAME: &str = "os";
+pub const LUA_STRLIBNAME: &str = "string";
+pub const LUA_UTF8LIBNAME: &str = "utf8";
+pub const LUA_BITLIBNAME: &str = "bit32";
+pub const LUA_MATHLIBNAME: &str = "math";
+pub const LUA_DBLIBNAME: &str = "debug";
+pub const LUA_LOADLIBNAME: &str = "package";
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua53", kind = "raw-dylib"))]
 extern "C-unwind" {
diff --git a/mlua-sys/src/lua54/lauxlib.rs b/mlua-sys/src/lua54/lauxlib.rs
index 8a1fd12..78b0881 100644
--- a/mlua-sys/src/lua54/lauxlib.rs
+++ b/mlua-sys/src/lua54/lauxlib.rs
@@ -9,10 +9,10 @@ use super::lua::{self, lua_CFunction, lua_Integer, lua_Number, lua_State};
 pub const LUA_ERRFILE: c_int = lua::LUA_ERRERR + 1;
 
 // Key, in the registry, for table of loaded modules
-pub const LUA_LOADED_TABLE: *const c_char = cstr!("_LOADED");
+pub const LUA_LOADED_TABLE: &str = "_LOADED";
 
 // Key, in the registry, for table of preloaded loaders
-pub const LUA_PRELOAD_TABLE: *const c_char = cstr!("_PRELOAD");
+pub const LUA_PRELOAD_TABLE: &str = "_PRELOAD";
 
 #[repr(C)]
 pub struct luaL_Reg {
diff --git a/mlua-sys/src/lua54/lualib.rs b/mlua-sys/src/lua54/lualib.rs
index dec577b..c104375 100644
--- a/mlua-sys/src/lua54/lualib.rs
+++ b/mlua-sys/src/lua54/lualib.rs
@@ -1,18 +1,18 @@
 //! Contains definitions from `lualib.h`.
 
-use std::os::raw::{c_char, c_int};
+use std::os::raw::c_int;
 
 use super::lua::lua_State;
 
-pub const LUA_COLIBNAME: *const c_char = cstr!("coroutine");
-pub const LUA_TABLIBNAME: *const c_char = cstr!("table");
-pub const LUA_IOLIBNAME: *const c_char = cstr!("io");
-pub const LUA_OSLIBNAME: *const c_char = cstr!("os");
-pub const LUA_STRLIBNAME: *const c_char = cstr!("string");
-pub const LUA_UTF8LIBNAME: *const c_char = cstr!("utf8");
-pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
-pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
-pub const LUA_LOADLIBNAME: *const c_char = cstr!("package");
+pub const LUA_COLIBNAME: &str = "coroutine";
+pub const LUA_TABLIBNAME: &str = "table";
+pub const LUA_IOLIBNAME: &str = "io";
+pub const LUA_OSLIBNAME: &str = "os";
+pub const LUA_STRLIBNAME: &str = "string";
+pub const LUA_UTF8LIBNAME: &str = "utf8";
+pub const LUA_MATHLIBNAME: &str = "math";
+pub const LUA_DBLIBNAME: &str = "debug";
+pub const LUA_LOADLIBNAME: &str = "package";
 
 #[cfg_attr(all(windows, raw_dylib), link(name = "lua54", kind = "raw-dylib"))]
 extern "C-unwind" {
diff --git a/mlua-sys/src/luau/lualib.rs b/mlua-sys/src/luau/lualib.rs
index 834f09e..0469bfd 100644
--- a/mlua-sys/src/luau/lualib.rs
+++ b/mlua-sys/src/luau/lualib.rs
@@ -1,19 +1,19 @@
 //! Contains definitions from `lualib.h`.
 
-use std::os::raw::{c_char, c_int};
+use std::os::raw::c_int;
 
 use super::lua::lua_State;
 
-pub const LUA_COLIBNAME: *const c_char = cstr!("coroutine");
-pub const LUA_TABLIBNAME: *const c_char = cstr!("table");
-pub const LUA_OSLIBNAME: *const c_char = cstr!("os");
-pub const LUA_STRLIBNAME: *const c_char = cstr!("string");
-pub const LUA_BITLIBNAME: *const c_char = cstr!("bit32");
-pub const LUA_BUFFERLIBNAME: *const c_char = cstr!("buffer");
-pub const LUA_UTF8LIBNAME: *const c_char = cstr!("utf8");
-pub const LUA_MATHLIBNAME: *const c_char = cstr!("math");
-pub const LUA_DBLIBNAME: *const c_char = cstr!("debug");
-pub const LUA_VECLIBNAME: *const c_char = cstr!("vector");
+pub const LUA_COLIBNAME: &str = "coroutine";
+pub const LUA_TABLIBNAME: &str = "table";
+pub const LUA_OSLIBNAME: &str = "os";
+pub const LUA_STRLIBNAME: &str = "string";
+pub const LUA_BITLIBNAME: &str = "bit32";
+pub const LUA_BUFFERLIBNAME: &str = "buffer";
+pub const LUA_UTF8LIBNAME: &str = "utf8";
+pub const LUA_MATHLIBNAME: &str = "math";
+pub const LUA_DBLIBNAME: &str = "debug";
+pub const LUA_VECLIBNAME: &str = "vector";
 
 extern "C-unwind" {
     pub fn luaopen_base(L: *mut lua_State) -> c_int;
diff --git a/src/state/raw.rs b/src/state/raw.rs
index e49156b..c40cd1a 100644
--- a/src/state/raw.rs
+++ b/src/state/raw.rs
@@ -1,6 +1,6 @@
 use std::any::TypeId;
 use std::cell::{Cell, UnsafeCell};
-use std::ffi::CStr;
+use std::ffi::{CStr, CString};
 use std::mem;
 use std::os::raw::{c_char, c_int, c_void};
 use std::panic::resume_unwind;
@@ -1285,14 +1285,16 @@ impl RawLua {
 
 // Uses 3 stack spaces
 unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()> {
-    unsafe fn requiref(
+    #[inline(always)]
+    pub unsafe fn requiref(
         state: *mut ffi::lua_State,
-        modname: *const c_char,
+        modname: &str,
         openf: ffi::lua_CFunction,
         glb: c_int,
     ) -> Result<()> {
-        protect_lua!(state, 0, 0, |state| {
-            ffi::luaL_requiref(state, modname, openf, glb)
+        let modname = mlua_expect!(CString::new(modname), "modname contains nil byte");
+        protect_lua!(state, 0, 1, |state| {
+            ffi::luaL_requiref(state, modname.as_ptr() as *const c_char, openf, glb)
         })
     }
 
@@ -1323,30 +1325,36 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
     {
         if libs.contains(StdLib::COROUTINE) {
             requiref(state, ffi::LUA_COLIBNAME, ffi::luaopen_coroutine, 1)?;
+            ffi::lua_pop(state, 1);
         }
     }
 
     if libs.contains(StdLib::TABLE) {
         requiref(state, ffi::LUA_TABLIBNAME, ffi::luaopen_table, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     #[cfg(not(feature = "luau"))]
     if libs.contains(StdLib::IO) {
         requiref(state, ffi::LUA_IOLIBNAME, ffi::luaopen_io, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     if libs.contains(StdLib::OS) {
         requiref(state, ffi::LUA_OSLIBNAME, ffi::luaopen_os, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     if libs.contains(StdLib::STRING) {
         requiref(state, ffi::LUA_STRLIBNAME, ffi::luaopen_string, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     #[cfg(any(feature = "lua54", feature = "lua53", feature = "luau"))]
     {
         if libs.contains(StdLib::UTF8) {
             requiref(state, ffi::LUA_UTF8LIBNAME, ffi::luaopen_utf8, 1)?;
+            ffi::lua_pop(state, 1);
         }
     }
 
@@ -1354,6 +1362,7 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
     {
         if libs.contains(StdLib::BIT) {
             requiref(state, ffi::LUA_BITLIBNAME, ffi::luaopen_bit32, 1)?;
+            ffi::lua_pop(state, 1);
         }
     }
 
@@ -1361,30 +1370,36 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
     {
         if libs.contains(StdLib::BIT) {
             requiref(state, ffi::LUA_BITLIBNAME, ffi::luaopen_bit, 1)?;
+            ffi::lua_pop(state, 1);
         }
     }
 
     #[cfg(feature = "luau")]
     if libs.contains(StdLib::BUFFER) {
         requiref(state, ffi::LUA_BUFFERLIBNAME, ffi::luaopen_buffer, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     #[cfg(feature = "luau")]
     if libs.contains(StdLib::VECTOR) {
         requiref(state, ffi::LUA_VECLIBNAME, ffi::luaopen_vector, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     if libs.contains(StdLib::MATH) {
         requiref(state, ffi::LUA_MATHLIBNAME, ffi::luaopen_math, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     if libs.contains(StdLib::DEBUG) {
         requiref(state, ffi::LUA_DBLIBNAME, ffi::luaopen_debug, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     #[cfg(not(feature = "luau"))]
     if libs.contains(StdLib::PACKAGE) {
         requiref(state, ffi::LUA_LOADLIBNAME, ffi::luaopen_package, 1)?;
+        ffi::lua_pop(state, 1);
     }
     #[cfg(feature = "luau")]
     if libs.contains(StdLib::PACKAGE) {
@@ -1395,11 +1410,13 @@ unsafe fn load_std_libs(state: *mut ffi::lua_State, libs: StdLib) -> Result<()>
     #[cfg(feature = "luajit")]
     if libs.contains(StdLib::JIT) {
         requiref(state, ffi::LUA_JITLIBNAME, ffi::luaopen_jit, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     #[cfg(feature = "luajit")]
     if libs.contains(StdLib::FFI) {
         requiref(state, ffi::LUA_FFILIBNAME, ffi::luaopen_ffi, 1)?;
+        ffi::lua_pop(state, 1);
     }
 
     Ok(())