draft thread-local state based on C11 TLS or pthreads

1 files changed, 34 insertions, 0 deletions

diff --git a/nonstd/static/thread.h b/nonstd/static/thread.h
index 00b40861..db66c0b7 100644
--- a/nonstd/static/thread.h
+++ b/nonstd/static/thread.h
@@ -1,5 +1,39 @@
+#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 201101L
+
+static struct per_thread *per_thread(void)
+{
+	_Thread_local static struct per_thread pt = {0};
+	return &pt;
+}
+
+#elif defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 199506L
+#include <pthread.h>
+
+static pthread_key_t __per_thread_key;
+
+static void _make_key(void)
+{
+	pthread_key_create(&key, NULL);
+}
+
+static struct per_thread *per_thread(void)
+{
+	static pthread_once_t key_once = PTHREAD_ONCE_INIT;
+	struct per_thread *pt;
+	pthread_once(&key_once, make_key);
+	if ((pt = pthread_getspecific(key)) == NULL) {
+		pt = calloc(1, sizeof (*pt));
+		pthread_setspecific(key, pt);
+	}
+	return pt;
+}
+
+#else
+
 static struct per_thread *per_thread(void)
 {
 	static struct per_thread pt = {0};
 	return &pt;
 }
+
+#endif