diff --git a/arena.h b/arena.h
index a4d59e3..737a7a9 100644
--- a/arena.h
+++ b/arena.h
@@ -9,6 +9,11 @@
 #define MA_GIB(x) (MA_MIB(x) * 1024ull)
 #define MA_TIB(x) (MA_GIB(x) * 1024ull)
 
+typedef struct MV_Memory MV_Memory;
+typedef struct MA_Checkpoint MA_Checkpoint;
+typedef struct MA_Arena MA_Arena;
+typedef struct M_Allocator M_Allocator;
+
 #ifndef MA_DEFAULT_RESERVE_SIZE
     #define MA_DEFAULT_RESERVE_SIZE MA_GIB(1)
 #endif
@@ -69,12 +74,7 @@ typedef enum M_AllocatorOp {
     M_AllocatorOp_Deallocate,
 } M_AllocatorOp;
 
-typedef struct MV_Memory MV_Memory;
-typedef struct MA_Checkpoint MA_Checkpoint;
-typedef struct MA_Arena MA_Arena;
-typedef struct M_Allocator M_Allocator;
 typedef void *M_AllocatorProc(void *allocator, M_AllocatorOp kind, void *p, size_t size);
-
 struct M_Allocator {
     void *obj;
     void *(*p)(void *allocator, M_AllocatorOp kind, void *p, size_t size);
diff --git a/array.hpp b/array.hpp
index 8e34edb..3c86613 100644
--- a/array.hpp
+++ b/array.hpp
@@ -1,4 +1,4 @@
-// #define ARRAY_ALLOCATOR_TYPE Allocator
+#pragma once
 
 #ifndef ARRAY_PRIVATE_FUNCTION
     #if defined(__GNUC__) || defined(__clang__)
diff --git a/clexer.h b/clexer.h
index 71c3bc7..718a232 100644
--- a/clexer.h
+++ b/clexer.h
@@ -1,5 +1,4 @@
-#ifndef CL_HEADER
-#define CL_HEADER
+#pragma once
 #include <stdint.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -494,5 +493,3 @@ CL_INLINE CL_Token *CL_MatchIdentifier(CL_Tokens *tokens, char *str) {
     }
     return 0;
 }
-
-#endif // CL_HEADER
diff --git a/filesystem.h b/filesystem.h
index f07726e..a0d0193 100644
--- a/filesystem.h
+++ b/filesystem.h
@@ -1,5 +1,4 @@
-#ifndef OS_FS_HEADER
-#define OS_FS_HEADER
+#pragma once
 
 #ifndef OS_API
     #ifdef __cplusplus
@@ -63,4 +62,3 @@ OS_API S8_String OS_ListDirRegexAsString(MA_Arena *arena, S8_String path, unsign
 OS_API bool OS_ExpandIncludesList(MA_Arena *arena, S8_List *out, S8_String filepath);
 OS_API S8_String OS_ExpandIncludes(MA_Arena *arena, S8_String filepath);
 OS_API bool WIN_EnableTerminalColors(void);
-#endif // OS_FS_HEADER
diff --git a/hash.h b/hash.h
index 35d06fd..faaeac6 100644
--- a/hash.h
+++ b/hash.h
@@ -1,5 +1,4 @@
-#ifndef HASH_HEADER
-#define HASH_HEADER
+#pragma once
 #include <stdint.h>
 
 #ifndef HASH_API_FUNCTION
@@ -19,15 +18,14 @@ struct RandomSeed {
 };
 
 //@begin gen_api_funcs
-HASH_API_FUNCTION uint64_t        HashBytes(void *data, uint64_t size);
-HASH_API_FUNCTION RandomSeed      MakeRandomSeed(uint64_t value);
-HASH_API_FUNCTION uint64_t        GetRandomU64(RandomSeed *state);
-HASH_API_FUNCTION int             GetRandomRangeI(RandomSeed *seed, int first, int last_included);
-HASH_API_FUNCTION double          GetRandomNormal(RandomSeed *series);
-HASH_API_FUNCTION double          GetRandomNormalRange(RandomSeed *seed, double min, double max);
-HASH_API_FUNCTION uint64_t        HashMix(uint64_t x, uint64_t y);
+HASH_API_FUNCTION uint64_t HashBytes(void *data, uint64_t size);
+HASH_API_FUNCTION RandomSeed MakeRandomSeed(uint64_t value);
+HASH_API_FUNCTION uint64_t GetRandomU64(RandomSeed *state);
+HASH_API_FUNCTION int GetRandomRangeI(RandomSeed *seed, int first, int last_included);
+HASH_API_FUNCTION double GetRandomNormal(RandomSeed *series);
+HASH_API_FUNCTION double GetRandomNormalRange(RandomSeed *seed, double min, double max);
+HASH_API_FUNCTION uint64_t HashMix(uint64_t x, uint64_t y);
 //@end gen_api_funcs
 
 #define WRAP_AROUND_POWER_OF_2(x, pow2) (((x) & ((pow2)-1llu)))
 static inline float GetRandomNormalF(RandomSeed *series) { return (float)GetRandomNormal(series); }
-#endif
diff --git a/io.h b/io.h
index 30e2a9d..678ca90 100644
--- a/io.h
+++ b/io.h
@@ -1,5 +1,4 @@
-#ifndef IO_HEADER
-#define IO_HEADER
+#pragma once
 #include <stdbool.h>
 
 #ifndef IO_API
@@ -72,4 +71,3 @@ IO_API void IO_OutputMessage(char *str, int len);
 IO_API IO_ErrorResult IO_OutputError(char *str, int len);
 IO_API void IO_Exit(int error_code);
 IO_API bool IO_IsDebuggerPresent(void);
-#endif
diff --git a/linked_list.h b/linked_list.h
index dc4f748..693ff98 100644
--- a/linked_list.h
+++ b/linked_list.h
@@ -1,6 +1,4 @@
-#ifndef LINKED_LIST_HEADER
-#define LINKED_LIST_HEADER
-
+#pragma once
 #define SLL_QUEUE_ADD_MOD(f, l, n, next) \
     do {                                 \
         (n)->next = 0;                   \
@@ -125,5 +123,3 @@
     } while (0)
 #define DLL_INSERT_NEXT(base, new) DLL_INSERT_NEXT_MOD(base, new, next, prev)
 #define DLL_INSERT_PREV(base, new) DLL_INSERT_NEXT_MOD(base, new, next, prev)
-
-#endif
\ No newline at end of file
diff --git a/load_library.h b/load_library.h
index cd7782c..327d4f8 100644
--- a/load_library.h
+++ b/load_library.h
@@ -1,6 +1,4 @@
-#ifndef LIB_LOAD_HEADER
-#define LIB_LOAD_HEADER
-
+#pragma once
 typedef void *LIB_Library;
 
 LIB_Library LIB_LoadLibrary(char *str);
@@ -10,5 +8,3 @@ bool LIB_UnloadLibrary(LIB_Library lib);
 #ifndef LIB_EXPORT
     #define LIB_EXPORT __declspec(dllexport)
 #endif
-
-#endif
\ No newline at end of file
diff --git a/multimedia.h b/multimedia.h
index 9d07fe6..ad69d95 100644
--- a/multimedia.h
+++ b/multimedia.h
@@ -1,5 +1,4 @@
-#ifndef MU_HEADER
-#define MU_HEADER
+#pragma once
 #include <stdbool.h>
 #include <stdint.h>
 #include <stddef.h>
@@ -367,5 +366,3 @@ typedef struct MU_Event {
 
 
     */
-
-#endif // MU_HEADER
diff --git a/preproc_env.h b/preproc_env.h
index 96ccbbe..5253ba0 100644
--- a/preproc_env.h
+++ b/preproc_env.h
@@ -1,6 +1,4 @@
-#ifndef PREPROC_ENV_HEADER
-#define PREPROC_ENV_HEADER
-
+#pragma once
 #ifndef _CRT_SECURE_NO_WARNINGS
     #define _CRT_SECURE_NO_WARNINGS
 #endif
@@ -86,5 +84,3 @@
 //     #pragma clang diagnostic push
 //     #pragma clang diagnostic ignored "-Wmicrosoft-enum-forward-reference"
 // #endif
-
-#endif // PREPROC_ENV_HEADER
\ No newline at end of file
diff --git a/regex.h b/regex.h
index 903443e..5223523 100644
--- a/regex.h
+++ b/regex.h
@@ -1,5 +1,4 @@
-#ifndef RE_HEADER
-#define RE_HEADER
+#pragma once
 #include <stdint.h>
 #include <stdbool.h>
 
@@ -92,5 +91,3 @@ RE_API RE_Match RE3_FindAgain(RE_Regex *regex, char *string, RE_Int len, RE_Matc
 RE_API RE_Int RE3_MatchFront(RE_Regex *regex, char *string, RE_Int len, char *string_front);
 RE_API RE_Regex *RE1_Parse(char *buff, RE_Int buffsize, char *string);
 RE_API RE_Regex *RE2_Parse(char *buff, RE_Int buffsize, char *string, RE_Int len);
-
-#endif // RE_HEADER
diff --git a/string.h b/string.h
index 3be747f..ffa23bf 100644
--- a/string.h
+++ b/string.h
@@ -1,5 +1,4 @@
-#ifndef S8_HEADER
-#define S8_HEADER
+#pragma once
 #include <stdint.h>
 #include <stdbool.h>
 
@@ -115,5 +114,3 @@ S8_API S8_List S8_CopyList(S8_Allocator allocator, S8_List a);
 S8_API S8_List S8_ConcatLists(S8_Allocator allocator, S8_List a, S8_List b);
 S8_API S8_Node *S8_AddNode(S8_Allocator allocator, S8_List *list, S8_String string);
 S8_API S8_String S8_AddF(S8_Allocator allocator, S8_List *list, const char *str, ...);
-
-#endif // S8_HEADER
diff --git a/table.hpp b/table.hpp
index cee9ba1..f3f9851 100644
--- a/table.hpp
+++ b/table.hpp
@@ -1,3 +1,4 @@
+#pragma once
 #include <stdint.h>
 /*
     Hash table implementation:
diff --git a/unicode.h b/unicode.h
index 65887bd..9b360dd 100644
--- a/unicode.h
+++ b/unicode.h
@@ -1,5 +1,4 @@
-#ifndef UTF_HEADER
-#define UTF_HEADER
+#pragma once
 #include <stdint.h>
 typedef struct UTF32_Result UTF32_Result;
 typedef struct UTF8_Result UTF8_Result;
@@ -51,4 +50,3 @@ UTF_API UTF8_Iter UTF8_IterateEx(char *str, int len);
 UTF_API UTF8_Iter UTF8_Iterate(char *str);
 
 #define UTF8_For(name, str, len) for (UTF8_Iter name = UTF8_IterateEx(str, (int)len); name.item; UTF8_Advance(&name))
-#endif // UTF_HEADER