From 4e1758fbf2261950df0d323460e7fbf35d402dd5 Mon Sep 17 00:00:00 2001
From: Elias Fleckenstein <eliasfleckenstein@web.de>
Date: Sun, 13 Feb 2022 16:25:40 +0100
Subject: [PATCH] Add flags

---
 flag.c | 34 ++++++++++++++++++++++++++++++++++
 flag.h | 19 +++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 flag.c
 create mode 100644 flag.h

diff --git a/flag.c b/flag.c
new file mode 100644
index 0000000..e7d1a6f
--- /dev/null
+++ b/flag.c
@@ -0,0 +1,34 @@
+#include <stdlib.h>
+#include "flag.h"
+
+Flag *flag_create()
+{
+	Flag *flag = malloc(sizeof *flag);
+	flag->done = false;
+	pthread_cond_init(&flag->cv, NULL);
+	pthread_mutex_init(&flag->mtx, NULL);
+	return flag;
+}
+
+void flag_delete(Flag *flag)
+{
+	pthread_cond_destroy(&flag->cv);	
+	pthread_mutex_destroy(&flag->mtx);
+	free(flag);
+}
+
+void flag_wait(Flag *flag)
+{
+	pthread_mutex_lock(&flag->mtx);
+	if (! flag->done)
+		pthread_cond_wait(&flag->cv, &flag->mtx);
+	pthread_mutex_unlock(&flag->mtx);
+}
+
+void flag_set(Flag *flag)
+{
+	pthread_mutex_lock(&flag->mtx);
+	flag->done = true;
+	pthread_cond_broadcast(&flag->cv);
+	pthread_mutex_unlock(&flag->mtx);
+}
diff --git a/flag.h b/flag.h
new file mode 100644
index 0000000..61e0be2
--- /dev/null
+++ b/flag.h
@@ -0,0 +1,19 @@
+#ifndef _DRAGONSTD_FLAG_H_
+#define _DRAGONSTD_FLAG_H_
+
+#include <stdbool.h>
+#include <stdatomic.h>
+#include <pthread.h>
+
+typedef struct {
+	atomic_bool done;
+	pthread_cond_t cv;
+	pthread_mutex_t mtx;
+} Flag;
+
+Flag *flag_create();
+void flag_delete(Flag *flag);
+void flag_set(Flag *flag);
+void flag_wait(Flag *flag);
+
+#endif
-- 
2.44.0