Mark cprintf buffer as thread_local

Author: Moe-hacker

Makefile

@@ -3,9 +3,9 @@ $(error config.mk is missing. Please run gen-config step before building.)
 endif
 include config.mk
 all :
-	$(CC) $(CFLAGS) cprintf.c main.c -o cprintf
+	$(CC) $(CFLAGS) -std=c11 cprintf.c main.c -o cprintf
 	$(STRIP) cprintf
 format :
 	clang-format -i include/cprintf.h cprintf.c test.c main.c
 test :
-	$(CC) -O0 -Wall -Wextra -Wgnu -std=c23 -pedantic -ggdb -fsanitize=address cprintf.c test.c
+	$(CC) -O0 -Wall -Wextra -Wgnu -std=c11 -pedantic -ggdb -fsanitize=address cprintf.c test.c

cprintf.c

@@ -31,8 +31,8 @@
 #define cprintf_strlen(f) (f == NULL ? 0 : strlen(f))
 #define cprintf_avoid_null(f) (f == NULL ? "" : f)
 #define cprintf_buf_len(f, d) (f != NULL ? (size_t)snprintf(NULL, 0, f, d) : 0)
-static char **cprintf_buffer = NULL;
-static size_t cprintf_buf_count = 0;
+static thread_local char **cprintf_buffer = NULL;
+static thread_local size_t cprintf_buf_count = 0;
 static void cprintf_mark_buf(char *b)
 {
 	cprintf_buffer = realloc(cprintf_buffer, (cprintf_buf_count + 1) * sizeof(char *));

include/cprintf.h

@@ -38,6 +38,7 @@
 #include <stdarg.h>
 #include <ctype.h>
 #include <sys/stat.h>
+#include <threads.h>
 #ifndef _Nullable
 #define _Nullable
 #endif