diff --git a/include/rexy/algorithm.tpp b/include/rexy/algorithm.tpp
index 555b1db..18bec37 100644
--- a/include/rexy/algorithm.tpp
+++ b/include/rexy/algorithm.tpp
@@ -19,8 +19,8 @@
 #ifndef REXY_ALGORITHM_TPP
 #define REXY_ALGORITHM_TPP
 
-#include <cstdint> //SIZE_MAX
-#include <cstdlib> //size_t
+#include <cstddef> //size_t
+#include <limits> //numeric_limits
 
 namespace rexy{
 
@@ -41,14 +41,14 @@ namespace rexy{
 	//Requires Iterators to be LegacyRandomAccessIterators
   template<class HIter, class NIter>
   constexpr HIter two_way_search(HIter hstart, HIter hend, NIter nstart, NIter nend){
-		size_t j = 0;
-		size_t i = 0;
-		size_t nlen = nend - nstart;
-		size_t hlen = hend - hstart;
+		std::size_t j = 0;
+		std::size_t i = 0;
+		std::size_t nlen = nend - nstart;
+		std::size_t hlen = hend - hstart;
 		auto [suffix, period] = detail::critical_factorization(nstart, nend);
 
 		if(detail::iter_compare(nstart, nstart + period, suffix)){
-			size_t memory = SIZE_MAX;
+			std::size_t memory = std::numeric_limits<std::size_t>::max();
 			while(j <= hlen - nlen){
 				i = max(suffix, memory) + 1;
 				//right side
@@ -68,7 +68,7 @@ namespace rexy{
 					memory = nlen - period - 1;
 				}else{
 					j += (i - suffix);
-					memory = SIZE_MAX;
+					memory = std::numeric_limits<std::size_t>::max();
 				}
 			}
 		}else{
@@ -83,10 +83,10 @@ namespace rexy{
 				if(i >= nlen){
 					i = suffix;
 					//left side
-					while(i != SIZE_MAX && nstart[i] == hstart[i + j]){
+					while(i != std::numeric_limits<std::size_t>::max() && nstart[i] == hstart[i + j]){
 						--i;
 					}
-					if(i == SIZE_MAX){
+					if(i == std::numeric_limits<std::size_t>::max()){
 						return hstart + j;
 					}
 					j += period;
diff --git a/include/rexy/allocator.hpp b/include/rexy/allocator.hpp
index 6178d43..35adb86 100644
--- a/include/rexy/allocator.hpp
+++ b/include/rexy/allocator.hpp
@@ -51,7 +51,7 @@ namespace rexy{
 		using void_pointer = void*;
 		using const_void_pointer = const void*;
 		using value_type = T;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using is_always_equal = std::true_type;
 		using propagate_on_container_copy_assignment = std::false_type;
diff --git a/include/rexy/buffer.hpp b/include/rexy/buffer.hpp
index 3784a5e..cc2d580 100644
--- a/include/rexy/buffer.hpp
+++ b/include/rexy/buffer.hpp
@@ -21,7 +21,7 @@
 
 #include "allocator.hpp"
 #include "detail/hasallocator.hpp"
-#include <cstdlib> //size_t, ptrdiff_t
+#include <cstddef> //size_t, ptrdiff_t
 #include <iterator> //reverse_iterator
 
 #include "compat/standard.hpp"
@@ -33,7 +33,7 @@ namespace rexy{
 	{
 	public:
 		using value_type = T;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using pointer = T*;
 		using const_pointer = const T*;
diff --git a/include/rexy/cx/array.hpp b/include/rexy/cx/array.hpp
index e0f54e7..b856e7c 100644
--- a/include/rexy/cx/array.hpp
+++ b/include/rexy/cx/array.hpp
@@ -27,12 +27,12 @@
 
 namespace rexy::cx{
 
-	template<class T, size_t N>
+	template<class T, std::size_t N>
 	class array
 	{
 	public:
 		using value_type = T;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using reference = T&;
 		using const_reference = const T&;
@@ -125,7 +125,7 @@ namespace rexy::cx{
 		}
 	};
 
-	template<size_t N>
+	template<std::size_t N>
 	class array<bool,N> : public detail::bool_specialize_base
 	{
 	public:
diff --git a/include/rexy/cx/cx_string_hash.hpp b/include/rexy/cx/cx_string_hash.hpp
index 9b273ca..7327d6b 100644
--- a/include/rexy/cx/cx_string_hash.hpp
+++ b/include/rexy/cx/cx_string_hash.hpp
@@ -24,7 +24,7 @@
 
 namespace rexy::cx{
 
-	template<size_t N>
+	template<std::size_t N>
 	struct hash<rexy::cx::string<N>> : public string_hash<rexy::cx::string<N>>{};
 
 }
diff --git a/include/rexy/cx/detail/bool_specialize_base.hpp b/include/rexy/cx/detail/bool_specialize_base.hpp
index b191dd6..1a3e422 100644
--- a/include/rexy/cx/detail/bool_specialize_base.hpp
+++ b/include/rexy/cx/detail/bool_specialize_base.hpp
@@ -29,7 +29,7 @@ namespace rexy::cx::detail{
 	class bool_specialize_base
 	{
 	protected:
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		static constexpr size_type bits_per_byte = CHAR_BIT;
 
@@ -91,10 +91,10 @@ namespace rexy::cx::detail{
 			constexpr booleans& operator=(const booleans&)noexcept = default;
 			constexpr booleans& operator=(booleans&&)noexcept = default;
 
-			constexpr boolean operator[](size_t i){
+			constexpr boolean operator[](std::size_t i){
 				return boolean{m_value, i};
 			}
-			constexpr boolean operator[](size_t i)const{
+			constexpr boolean operator[](std::size_t i)const{
 				return boolean{const_cast<uchar&>(m_value), i};
 			}
 			constexpr uchar& data(void){
diff --git a/include/rexy/cx/hashmap.hpp b/include/rexy/cx/hashmap.hpp
index 888819e..275a7b5 100644
--- a/include/rexy/cx/hashmap.hpp
+++ b/include/rexy/cx/hashmap.hpp
@@ -25,7 +25,7 @@
 #include "../hash.hpp"
 
 #include <climits> //CHAR_BIT
-#include <cstddef> //size_t, ptrdiff_t
+#include <cstddef> //std::size_t, ptrdiff_t
 #include <type_traits> //decay
 #include <initializer_list>
 
@@ -42,14 +42,14 @@ namespace rexy::cx{
 	template<class Key, class Value>
 	element(Key,Value) -> element<Key,Value>;
 
-	template<class Key, class Value, size_t N, class Hash = hash<Key>>
+	template<class Key, class Value, std::size_t N, class Hash = hash<Key>>
 	class hashmap
 	{
 	public:
 		using key_type = Key;
 		using mapped_type = Value;
 		using value_type = element<Key,Value>;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using hasher = Hash;
 		using reference = mapped_type&;
@@ -72,7 +72,7 @@ namespace rexy::cx{
 			noexcept(std::is_nothrow_default_constructible<value_type>::value &&
 			         std::is_nothrow_copy_constructible<value_type>::value &&
 			         std::is_nothrow_move_assignable<mapped_type>::value &&
-			         std::is_nothrow_invocable<Hash,Key,size_t>::value);
+			         std::is_nothrow_invocable<Hash,Key,std::size_t>::value);
 
 		//no key checks. give a correct key or get a random answer :)
 		template<class U, class UHash = hash<std::decay_t<U>>>
diff --git a/include/rexy/cx/hashmap.tpp b/include/rexy/cx/hashmap.tpp
index 687239a..daa232a 100644
--- a/include/rexy/cx/hashmap.tpp
+++ b/include/rexy/cx/hashmap.tpp
@@ -23,12 +23,12 @@
 
 namespace rexy::cx{
 
-	template<class Key, class Value, size_t N, class Hash>
+	template<class Key, class Value, std::size_t N, class Hash>
 	constexpr hashmap<Key,Value,N,Hash>::hashmap(const value_type(&elements)[N])
 		noexcept(std::is_nothrow_default_constructible<value_type>::value &&
 		         std::is_nothrow_copy_constructible<value_type>::value &&
 		         std::is_nothrow_move_assignable<mapped_type>::value &&
-		         std::is_nothrow_invocable<Hash,Key,size_t>::value)
+		         std::is_nothrow_invocable<Hash,Key,std::size_t>::value)
 	{
 		array<vector<value_type,N>,N> buckets;
 		array<size_type,N> key_hashes; //full hash values for keys to verify good index values
@@ -101,7 +101,7 @@ namespace rexy::cx{
 	}
 
 	//no key checks. give a correct key or get a random answer :)
-	template<class Key, class Value, size_t N, class Hash>
+	template<class Key, class Value, std::size_t N, class Hash>
 	template<class U, class UHash>
 	constexpr auto hashmap<Key,Value,N,Hash>::operator[](U&& key)noexcept -> reference{
 		auto d = m_g[UHash{}(std::forward<U>(key), 0) % max_size];
@@ -109,7 +109,7 @@ namespace rexy::cx{
 			return m_elements[d & ~single_bucket_bit].value;
 		return m_elements[UHash{}(std::forward<U>(key), d) % max_size].value;
 	}
-	template<class Key, class Value, size_t N, class Hash>
+	template<class Key, class Value, std::size_t N, class Hash>
 	template<class U, class UHash>
 	constexpr auto hashmap<Key,Value,N,Hash>::operator[](U&& key)const noexcept -> const_reference{
 		auto d = m_g[UHash{}(std::forward<U>(key), 0) % max_size];
@@ -118,7 +118,7 @@ namespace rexy::cx{
 		return m_elements[UHash{}(std::forward<U>(key), d) % max_size].value;
 	}
 
-	template<class Key, class Value, size_t N, class Hash>
+	template<class Key, class Value, std::size_t N, class Hash>
 	template<class U, class UHash>
 	constexpr bool hashmap<Key,Value,N,Hash>::contains(U&& key)const noexcept{
 		const auto hashval = UHash{}(std::forward<U>(key), 0);
@@ -129,7 +129,7 @@ namespace rexy::cx{
 		return m_elements[UHash{}(std::forward<U>(key), d) % max_size].key == std::forward<U>(key);
 	}
 
-	template<class Key, class Value, size_t N, class Hash = hash<Key>>
+	template<class Key, class Value, std::size_t N, class Hash = hash<Key>>
 	constexpr auto make_hashmap(const typename hashmap<Key,Value,N,Hash>::value_type(&list)[N]){
 		return hashmap<Key,Value,N,Hash>(list);
 	}
diff --git a/include/rexy/cx/string.hpp b/include/rexy/cx/string.hpp
index bcfdc80..65ba621 100644
--- a/include/rexy/cx/string.hpp
+++ b/include/rexy/cx/string.hpp
@@ -42,7 +42,7 @@ namespace rexy::cx{
 
 namespace rexy::cx{
 
-	template<size_t N, class Char = char>
+	template<std::size_t N, class Char = char>
 	class string
 	{
 	public:
diff --git a/include/rexy/cx/vector.hpp b/include/rexy/cx/vector.hpp
index d01719c..533c2e3 100644
--- a/include/rexy/cx/vector.hpp
+++ b/include/rexy/cx/vector.hpp
@@ -30,12 +30,12 @@
 
 namespace rexy::cx{
 
-	template<class T, size_t N>
+	template<class T, std::size_t N>
 	class vector
 	{
 	public:
 		using value_type = T;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using iterator = T*;
 		using const_iterator = const T*;
@@ -244,7 +244,7 @@ namespace rexy::cx{
 		}
 	};
 
-	template<size_t N>
+	template<std::size_t N>
 	class vector<bool,N> : public detail::bool_specialize_base
 	{
 	public:
diff --git a/include/rexy/deferred.hpp b/include/rexy/deferred.hpp
index d246b09..af47af5 100644
--- a/include/rexy/deferred.hpp
+++ b/include/rexy/deferred.hpp
@@ -46,7 +46,7 @@ namespace rexy{
 		constexpr operator value_type(void);
 
 	private:
-		template<size_t... Is>
+		template<std::size_t... Is>
 		constexpr value_type get_value_(std::index_sequence<Is...>);
 	};
 
@@ -70,7 +70,7 @@ namespace rexy{
 		constexpr operator ret_t(void);
 
 	private:
-		template<size_t... Is>
+		template<std::size_t... Is>
 		constexpr decltype(auto) get_value_(std::index_sequence<Is...>);
 	};
 
@@ -87,7 +87,7 @@ namespace rexy{
 		return get_value_(std::make_index_sequence<sizeof...(Args)>());
 	}
 	template<class T, class... Args>
-	template<size_t... Is>
+	template<std::size_t... Is>
 	constexpr auto deferred<T,Args...>::get_value_(std::index_sequence<Is...>) -> value_type{
 		return T{std::forward<std::tuple_element_t<Is,decltype(m_args)>>(std::get<Is>(m_args))...};
 	}
@@ -112,7 +112,7 @@ namespace rexy{
 		return get_value_(std::make_index_sequence<sizeof...(Args)>());
 	}
 	template<class Fn, class... Args>
-	template<size_t... Is>
+	template<std::size_t... Is>
 	constexpr decltype(auto) deferred_function<Fn,Args...>::get_value_(std::index_sequence<Is...>){
 		return std::forward<Fn>(m_fn)(std::forward<std::tuple_element_t<Is,decltype(m_args)>>(std::get<Is>(m_args))...);
 	}
diff --git a/include/rexy/detail/algorithm.hpp b/include/rexy/detail/algorithm.hpp
index 1e5c561..52965ec 100644
--- a/include/rexy/detail/algorithm.hpp
+++ b/include/rexy/detail/algorithm.hpp
@@ -25,7 +25,7 @@
 #include <functional> //less, greater
 #include <utility> //pair
 #include <iterator> //iterator_traits
-#include <cstdlib> //size_t
+#include <cstddef> //size_t
 
 namespace rexy::detail{
 
@@ -51,12 +51,12 @@ namespace rexy::detail{
 		return left;
 	}
 	template<class Iter, class Op>
-	constexpr std::pair<size_t,size_t> max_suffix(const Iter& needle, size_t nlen, const Op& op = Op()){
+	constexpr std::pair<std::size_t,size_t> max_suffix(const Iter& needle, std::size_t nlen, const Op& op = Op()){
 		using value_type = typename std::iterator_traits<Iter>::value_type;
-		size_t max_suffix = -1;
-		size_t j = 0;
-		size_t k = 1;
-		size_t period = 1;
+		std::size_t max_suffix = -1;
+		std::size_t j = 0;
+		std::size_t k = 1;
+		std::size_t period = 1;
 		value_type a;
 		value_type b;
 
@@ -82,7 +82,7 @@ namespace rexy::detail{
 		return {max_suffix, period};
 	}
 	template<class Iter>
-	constexpr std::pair<size_t,size_t> critical_factorization(const Iter& nstart, const Iter& nend){
+	constexpr std::pair<std::size_t,size_t> critical_factorization(const Iter& nstart, const Iter& nend){
 		auto msuffix = max_suffix(nstart, nend - nstart, std::less{});
 		auto msuffix_rev = max_suffix(nstart, nend - nstart, std::greater{});
 		if(msuffix.first < msuffix_rev.first){
@@ -91,8 +91,8 @@ namespace rexy::detail{
 		return msuffix;
 	}
 	template<class Iter>
-	constexpr bool iter_compare(const Iter& left, const Iter& right, size_t length){
-		for(size_t i = 0;i < length;++i){
+	constexpr bool iter_compare(const Iter& left, const Iter& right, std::size_t length){
+		for(std::size_t i = 0;i < length;++i){
 			if(left[i] != right[i])
 				return false;
 		}
diff --git a/include/rexy/detail/format/formatter.hpp b/include/rexy/detail/format/formatter.hpp
index a24c1f1..0ec90ba 100644
--- a/include/rexy/detail/format/formatter.hpp
+++ b/include/rexy/detail/format/formatter.hpp
@@ -19,7 +19,7 @@
 #ifndef REXY_DETAIL_FORMAT_FORMATTER_HPP
 #define REXY_DETAIL_FORMAT_FORMATTER_HPP
 
-#include <cstddef> //size_t, nullptr_t
+#include <cstddef> //std::size_t, nullptr_t
 #include <variant> //monostate
 #include <locale> //locale
 #include <type_traits> //remove_cvref
diff --git a/include/rexy/filerd.hpp b/include/rexy/filerd.hpp
index bd69ad0..64e3843 100644
--- a/include/rexy/filerd.hpp
+++ b/include/rexy/filerd.hpp
@@ -54,9 +54,9 @@ namespace rexy{
 
 		void reset(FILE* fp = nullptr)noexcept;
 		FILE* release(void)noexcept;
-		size_t length(void)noexcept;
-		size_t position(void)const noexcept;
-		void rewind(size_t pos = 0)noexcept;
+		std::size_t length(void)noexcept;
+		std::size_t position(void)const noexcept;
+		void rewind(std::size_t pos = 0)noexcept;
 
 		operator FILE*(void)noexcept;
 		operator const FILE*(void)const noexcept;
@@ -64,13 +64,13 @@ namespace rexy{
 		const FILE* get(void)const noexcept;
 		operator bool(void)const noexcept;
 
-		size_t read(char* dest, size_t bytes)noexcept;
-		rexy::string read(size_t bytes)noexcept;
-		rexy::string readln(size_t max = 0)noexcept;
-		rexy::buffer<char> read_bin(size_t bytes)noexcept(std::is_nothrow_constructible<rexy::buffer<char>, char*, size_t>::value);
+		std::size_t read(char* dest, std::size_t bytes)noexcept;
+		rexy::string read(std::size_t bytes)noexcept;
+		rexy::string readln(std::size_t max = 0)noexcept;
+		rexy::buffer<char> read_bin(std::size_t bytes)noexcept(std::is_nothrow_constructible<rexy::buffer<char>, char*, std::size_t>::value);
 
-		size_t write(const char* c, size_t bytes)noexcept;
-		size_t write(const rexy::string_base<char>& s)noexcept;
+		std::size_t write(const char* c, std::size_t bytes)noexcept;
+		std::size_t write(const rexy::string_base<char>& s)noexcept;
 	};
 
 }
diff --git a/include/rexy/hash.hpp b/include/rexy/hash.hpp
index 52c5afd..9695530 100644
--- a/include/rexy/hash.hpp
+++ b/include/rexy/hash.hpp
@@ -26,11 +26,11 @@ namespace rexy{
 
 	template<class T>
 	struct hash{
-		constexpr size_t operator()(const T& t, size_t salt = 0)const noexcept{
-			constexpr size_t bytes = sizeof(size_t);
-			size_t val = static_cast<size_t>(t);
-			size_t hash = 5381 + salt; //magic hash number
-			for(size_t i = 0;i < bytes;++i){
+		constexpr std::size_t operator()(const T& t, std::size_t salt = 0)const noexcept{
+			constexpr std::size_t bytes = sizeof(std::size_t);
+			std::size_t val = static_cast<std::size_t>(t);
+			std::size_t hash = 5381 + salt; //magic hash number
+			for(std::size_t i = 0;i < bytes;++i){
 				unsigned char c = static_cast<unsigned char>(val >> (i * CHAR_BIT));
 				hash = ((hash << 5) + hash) ^ c;
 			}
diff --git a/include/rexy/mpmc_queue.hpp b/include/rexy/mpmc_queue.hpp
index 25602cb..84957fa 100644
--- a/include/rexy/mpmc_queue.hpp
+++ b/include/rexy/mpmc_queue.hpp
@@ -20,7 +20,7 @@
 #define REXY_MPMC_QUEUE_HPP
 
 #include <vector> //vector (duh)
-#include <cstdlib> //size_t
+#include <cstddef> //size_t
 #include <atomic> //atomic (duh)
 
 #include "rexy.hpp"
@@ -43,7 +43,7 @@ namespace rexy{
 	{
 	public:
 		using value_type = T;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using pointer = value_type*;
 		using const_pointer = const value_type*;
 		using reference = value_type&;
@@ -55,13 +55,13 @@ namespace rexy{
 		//libc++ bug
 		// https://bugs.llvm.org/show_bug.cgi?id=41423
 		#if defined(_LIBCPP_VERSION) && _LIBCPP_VERSION >= 12000
-			static constexpr size_t cacheline_size = std::hardware_destructive_interference_size;
+			static constexpr std::size_t cacheline_size = std::hardware_destructive_interference_size;
 		#else
-			static constexpr size_t cacheline_size = 64;
+			static constexpr std::size_t cacheline_size = 64;
 		#endif
 	#else
 		//Best guess
-		static constexpr size_t cacheline_size = 64;
+		static constexpr std::size_t cacheline_size = 64;
 	#endif
 
 		class slot
diff --git a/include/rexy/string_base.hpp b/include/rexy/string_base.hpp
index 565915d..fe5003b 100644
--- a/include/rexy/string_base.hpp
+++ b/include/rexy/string_base.hpp
@@ -21,7 +21,7 @@
 
 #include <type_traits> //is_same, integral_contant, enable_if, etc
 #include <utility> //forward
-#include <cstddef> //size_t,ptrdiff
+#include <cstddef> //std::size_t,ptrdiff
 #include <cstring> //strlen
 #include <climits> //CHAR_BIT
 #include <iterator> //reverse_iterator
@@ -54,7 +54,7 @@ namespace rexy{
 	{
 	public:
 		using value_type = Char;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using pointer = value_type*;
 		using const_pointer = const value_type*;
diff --git a/include/rexy/string_hash.hpp b/include/rexy/string_hash.hpp
index 42b0175..1c823bf 100644
--- a/include/rexy/string_hash.hpp
+++ b/include/rexy/string_hash.hpp
@@ -26,9 +26,9 @@ namespace rexy{
 	//jenkns one at a time hash
 	template<class Str>
 	struct string_hash{
-		constexpr size_t operator()(const Str& s, size_t salt = 0)const noexcept{
-			size_t hash = salt;
-			for(size_t i = 0;i < s.length();++i){
+		constexpr std::size_t operator()(const Str& s, std::size_t salt = 0)const noexcept{
+			std::size_t hash = salt;
+			for(std::size_t i = 0;i < s.length();++i){
 				hash += s[i];
 				hash += (hash << 10);
 				hash += (hash >> 6);
diff --git a/include/rexy/string_view.hpp b/include/rexy/string_view.hpp
index 26ede80..5188ac1 100644
--- a/include/rexy/string_view.hpp
+++ b/include/rexy/string_view.hpp
@@ -19,7 +19,7 @@
 #ifndef REXY_STRING_VIEW_HPP
 #define REXY_STRING_VIEW_HPP
 
-#include <cstddef> //size_t, ptrdiff_t
+#include <cstddef> //std::size_t, ptrdiff_t
 #include <iterator> //reverse_iterator
 
 #include "compat/standard.hpp"
@@ -35,7 +35,7 @@ namespace rexy{
 	{
 	public:
 		using value_type = Char;
-		using size_type = size_t;
+		using size_type = std::size_t;
 		using difference_type = ptrdiff_t;
 		using pointer = value_type*;
 		using const_pointer = const value_type*;
@@ -132,7 +132,7 @@ namespace rexy{
 	template<class T>
 	basic_string_view(const T*) -> basic_string_view<T>;
 	template<class T>
-	basic_string_view(const T*, size_t) -> basic_string_view<T>;
+	basic_string_view(const T*, std::size_t) -> basic_string_view<T>;
 
 	using string_view = basic_string_view<char>;
 	using wstring_view = basic_string_view<wchar_t>;
@@ -146,16 +146,16 @@ namespace rexy{
 
 	inline namespace str_literals{
 
-		constexpr inline rexy::basic_string_view<char> operator"" _sv(const char* str, size_t len)noexcept{
+		constexpr inline rexy::basic_string_view<char> operator"" _sv(const char* str, std::size_t len)noexcept{
 			return rexy::basic_string_view(str, len);
 		}
-		constexpr inline rexy::basic_string_view<wchar_t> operator"" _sv(const wchar_t* str, size_t len)noexcept{
+		constexpr inline rexy::basic_string_view<wchar_t> operator"" _sv(const wchar_t* str, std::size_t len)noexcept{
 			return rexy::basic_string_view(str, len);
 		}
-		constexpr inline rexy::basic_string_view<char16_t> operator"" _sv(const char16_t* str, size_t len)noexcept{
+		constexpr inline rexy::basic_string_view<char16_t> operator"" _sv(const char16_t* str, std::size_t len)noexcept{
 			return rexy::basic_string_view(str, len);
 		}
-		constexpr inline rexy::basic_string_view<char32_t> operator"" _sv(const char32_t* str, size_t len)noexcept{
+		constexpr inline rexy::basic_string_view<char32_t> operator"" _sv(const char32_t* str, std::size_t len)noexcept{
 			return rexy::basic_string_view(str, len);
 		}
 
diff --git a/include/rexy/utility.hpp b/include/rexy/utility.hpp
index 43bcc34..75f39ad 100644
--- a/include/rexy/utility.hpp
+++ b/include/rexy/utility.hpp
@@ -20,7 +20,7 @@
 #define REXY_UTILITY_HPP
 
 #include <utility> //forward, move
-#include <cstdlib> //size_t
+#include <cstddef> //size_t
 #include <type_traits>
 #include <cstring> //strlen, strcmp, memcpy
 #include <cwchar> //wcslen
@@ -50,7 +50,7 @@ namespace rexy{
 			}
 			return start2;
 		}
-		template<class T, size_t N>
+		template<class T, std::size_t N>
 		constexpr void swap(T (&l)[N], T (&r)[N])
 			noexcept(noexcept(swap(*l, *r)))
 		{
@@ -94,7 +94,7 @@ namespace rexy{
 
 #ifdef REXY_if_consteval
 		template<class T>
-		constexpr size_t strlen(const T* c)noexcept{
+		constexpr std::size_t strlen(const T* c)noexcept{
 			return std::char_traits<T>::length(c);
 		}
 		template<class T>
@@ -138,13 +138,13 @@ namespace rexy{
 			for(;cmp(*l, *r) && *l;++l, ++r);
 			return *l - *r;
 		}
-		constexpr void memcpy(void* l, const void* r, size_t n){
+		constexpr void memcpy(void* l, const void* r, std::size_t n){
 			REXY_if_consteval{
 				std::memcpy(l, r, n);
 			}else{
 				char* ld = static_cast<char*>(l);
 				const char* rd = static_cast<const char*>(r);
-				for(size_t i = 0;i < n;++i){
+				for(std::size_t i = 0;i < n;++i){
 					ld[i] = rd[i];
 				}
 			}
@@ -152,8 +152,8 @@ namespace rexy{
 	}
 #else // REXY_if_consteval
 		template<class T>
-		constexpr size_t strlen(const T* c)noexcept{
-			size_t i = 0;
+		constexpr std::size_t strlen(const T* c)noexcept{
+			std::size_t i = 0;
 			for(;c[i];++i);
 			return i;
 		}
@@ -172,10 +172,10 @@ namespace rexy{
 			for(std::size_t i = 0;*l == *r && *l && i < max;++i, ++l, ++r);
 			return *l - *r;
 		}
-		constexpr void memcpy(void* l, const void* r, size_t n){
+		constexpr void memcpy(void* l, const void* r, std::size_t n){
 			char* ld = static_cast<char*>(l);
 			const char* rd = static_cast<const char*>(r);
-			for(size_t i = 0;i < n;++i){
+			for(std::size_t i = 0;i < n;++i){
 				ld[i] = rd[i];
 			}
 		}
diff --git a/src/filerd.cpp b/src/filerd.cpp
index 33e6e84..8ea30aa 100644
--- a/src/filerd.cpp
+++ b/src/filerd.cpp
@@ -39,20 +39,20 @@ namespace rexy{
 	FILE* filerd::release(void)noexcept{
 		return std::exchange(m_fp, nullptr);
 	}
-	size_t filerd::length(void)noexcept{
+	std::size_t filerd::length(void)noexcept{
 		if(!m_fp)
 			return 0;
-		size_t tmp, ret;
+		std::size_t tmp, ret;
 		tmp = ftell(m_fp);
 		fseek(m_fp, 0, SEEK_END);
 		ret = ftell(m_fp);
 		fseek(m_fp, tmp, SEEK_SET);
 		return ret;
 	}
-	size_t filerd::position(void)const noexcept{
+	std::size_t filerd::position(void)const noexcept{
 		return ftell(m_fp);
 	}
-	void filerd::rewind(size_t pos)noexcept{
+	void filerd::rewind(std::size_t pos)noexcept{
 		fseek(m_fp, pos, SEEK_SET);
 	}
 
@@ -72,20 +72,20 @@ namespace rexy{
 		return m_fp;
 	}
 
-	size_t filerd::read(char* dest, size_t bytes)noexcept{
+	std::size_t filerd::read(char* dest, std::size_t bytes)noexcept{
 		return fread(dest, 1, bytes, m_fp);
 	}
-	rexy::string filerd::read(size_t bytes)noexcept{
+	rexy::string filerd::read(std::size_t bytes)noexcept{
 		rexy::string ret;
 		char* tmp = ret.allocator().allocate(bytes);
-		size_t written = read(tmp, bytes);
+		std::size_t written = read(tmp, bytes);
 		ret.reset(tmp, written);
 		return ret;
 	}
-	rexy::string filerd::readln(size_t max)noexcept{
+	rexy::string filerd::readln(std::size_t max)noexcept{
 		rexy::string ret;
 		int c;
-		size_t count = 0;
+		std::size_t count = 0;
 		for(c = fgetc(m_fp);c != EOF && c != '\n';c = fgetc(m_fp)){
 			char ch = c;
 			ret.append(&ch, 1);
@@ -94,18 +94,18 @@ namespace rexy{
 		}
 		return ret;
 	}
-	rexy::buffer<char> filerd::read_bin(size_t bytes)
-		noexcept(std::is_nothrow_constructible<rexy::buffer<char>, char*, size_t>::value)
+	rexy::buffer<char> filerd::read_bin(std::size_t bytes)
+		noexcept(std::is_nothrow_constructible<rexy::buffer<char>, char*, std::size_t>::value)
 	{
 		rexy::buffer<char> ret{bytes};
-		size_t written = read(ret.data(), bytes);
+		std::size_t written = read(ret.data(), bytes);
 		ret.set_size(written);
 		return ret;
 	}
-	size_t filerd::write(const char* c, size_t bytes)noexcept{
+	std::size_t filerd::write(const char* c, std::size_t bytes)noexcept{
 		return fwrite(c, 1, bytes, m_fp);
 	}
-	size_t filerd::write(const rexy::string_base<char>& c)noexcept{
+	std::size_t filerd::write(const rexy::string_base<char>& c)noexcept{
 		return write(c.data(), c.length());
 	}
 
diff --git a/src/threadpool.cpp b/src/threadpool.cpp
index cfe3b25..315490d 100644
--- a/src/threadpool.cpp
+++ b/src/threadpool.cpp
@@ -52,7 +52,7 @@ namespace rexy{
 		m_valid(true)
 	{
 		m_ctor_lock.unlock();
-		for(size_t i = 0;i < other.m_workers.size();++i){
+		for(std::size_t i = 0;i < other.m_workers.size();++i){
 			m_workers.emplace_back(&threadpool::worker_loop, this);
 		}
 		m_qcv.notify_all();
diff --git a/tests/basic_string.cpp b/tests/basic_string.cpp
index 4551d32..d32c34a 100644
--- a/tests/basic_string.cpp
+++ b/tests/basic_string.cpp
@@ -90,7 +90,7 @@ void check_short_construction(){
 }
 void check_long_construction(){
 	const char* data = "this is a really long string that should ensure that it makes a dynamic allocation even if it has a big buffer.";
-	size_t len = strlen(data);
+	std::size_t len = strlen(data);
 	test_str str1(data);
 	if(str1.length() != len)
 		error("long constructed string should be length() == strlen(data)\n");
@@ -171,7 +171,7 @@ void check_long_assignment(){
 	const char* startdata1 = "this is another really long string that should ensure that it makes some sort of dyn alloc for big buf";
 	const char* startdata2 = "zy";
 	const char* data = "this is a really long string that should ensure that it makes a dynamic allocation even if it has a big buffer.";
-	size_t len = strlen(data);
+	std::size_t len = strlen(data);
 	test_str str1(startdata1);
 	str1 = data;
 	if(str1.length() != len)