From 4efbe8eca395c90fc0053c7ba1038ccb7bf69e61 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Fri, 10 Nov 2023 09:58:57 -0500
Subject: config: Add constants for C standard versions

---
 src/bit.h    |  8 ++++----
 src/config.h | 10 +++++++++-
 src/diag.h   |  4 ++--
 src/thread.h |  2 +-
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/bit.h b/src/bit.h
index 3f756f6..21a8076 100644
--- a/src/bit.h
+++ b/src/bit.h
@@ -12,7 +12,7 @@
 #include <limits.h>
 #include <stdint.h>
 
-#if __STDC_VERSION__ >= 202311L
+#if __STDC_VERSION__ >= C23
 #  include <stdbit.h>
 #endif
 
@@ -173,7 +173,7 @@
 #  define ENDIAN_NATIVE 0
 #endif
 
-#if __STDC_VERSION__ >= 202311L
+#if __STDC_VERSION__ >= C23
 #  define bswap16 stdc_memreverse8u16
 #  define bswap32 stdc_memreverse8u32
 #  define bswap64 stdc_memreverse8u64
@@ -236,7 +236,7 @@ static inline uint8_t bswap8(uint8_t n) {
 
 // C23 polyfill: bit utilities
 
-#if __STDC_VERSION__ >= 202311L
+#if __STDC_VERSION__ >= C23
 #  define count_ones stdc_count_ones
 #  define count_zeros stdc_count_zeros
 #  define rotate_left stdc_rotate_left
@@ -395,6 +395,6 @@ UINT_OVERLOADS(BIT_CEIL)
 #define bit_floor(n) UINT_SELECT(n, bit_floor)(n)
 #define bit_ceil(n) UINT_SELECT(n, bit_ceil)(n)
 
-#endif // __STDC_VERSION__ < 202311L
+#endif // __STDC_VERSION__ < C23
 
 #endif // BFS_BIT_H
diff --git a/src/config.h b/src/config.h
index db62ef8..821e4a9 100644
--- a/src/config.h
+++ b/src/config.h
@@ -8,9 +8,17 @@
 #ifndef BFS_CONFIG_H
 #define BFS_CONFIG_H
 
+// Possible __STDC_VERSION__ values
+
+#define C95 199409L
+#define C99 199901L
+#define C11 201112L
+#define C17 201710L
+#define C23 202311L
+
 #include <stddef.h>
 
-#if __STDC_VERSION__ < 202311L
+#if __STDC_VERSION__ < C23
 #  include <stdalign.h>
 #  include <stdbool.h>
 #  include <stdnoreturn.h>
diff --git a/src/diag.h b/src/diag.h
index 870264e..981419e 100644
--- a/src/diag.h
+++ b/src/diag.h
@@ -14,7 +14,7 @@
 /**
  * static_assert() with an optional second argument.
  */
-#if __STDC_VERSION__ >= 202311L
+#if __STDC_VERSION__ >= C23
 #  define bfs_static_assert static_assert
 #else
 #  define bfs_static_assert(...) bfs_static_assert_(__VA_ARGS__, #__VA_ARGS__, )
@@ -35,7 +35,7 @@ struct bfs_loc {
 /**
  * Get the current source code location.
  */
-#if __STDC_VERSION__ >= 202311L
+#if __STDC_VERSION__ >= C23
 #  define bfs_location() (&(static const struct bfs_loc)BFS_LOC_INIT)
 #else
 #  define bfs_location() (&(const struct bfs_loc)BFS_LOC_INIT)
diff --git a/src/thread.h b/src/thread.h
index b37d45f..8174fe4 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -11,7 +11,7 @@
 #include "config.h"
 #include <pthread.h>
 
-#if __STDC_VERSION__ < 202311L && !defined(thread_local)
+#if __STDC_VERSION__ < C23 && !defined(thread_local)
 #  if BFS_USE_THREADS_H
 #    include <threads.h>
 #  else
-- 
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