1 files changed, 57 insertions, 0 deletions
diff --git a/inc/dnbd3/shared/fdsignal.h b/inc/dnbd3/shared/fdsignal.h
new file mode 100644
index 0000000..960a2a9
--- /dev/null
+++ b/inc/dnbd3/shared/fdsignal.h
@@ -0,0 +1,57 @@
+#ifndef _FD_SIGNAL_H_
+#define _FD_SIGNAL_H_
+
+#define SIGNAL_OK (0)
+#define SIGNAL_TIMEOUT (-2)
+#define SIGNAL_ERROR (-1)
+
+typedef struct _dnbd3_signal dnbd3_signal_t;
+
+/**
+ * Create a new signal, nonblocking.
+ * @return NULL on error, pointer to dnbd3_signal_t on success.
+ */
+dnbd3_signal_t* signal_new();
+
+/**
+ * Create a new signal, blocking.
+ * @return NULL on error, pointer to dnbd3_signal_t on success.
+ */
+dnbd3_signal_t* signal_newBlocking();
+
+/**
+ * Trigger the given signal, so a wait or clear call will succeed.
+ * @return SIGNAL_OK on success, SIGNAL_ERROR on error
+ */
+int signal_call(const dnbd3_signal_t* const signal);
+
+/**
+ * Wait for given signal, with an optional timeout.
+ * If timeout == 0, just poll once.
+ * If timeout < 0, wait forever.
+ * @return > 0 telling how many times the signal was called,
+ *    SIGNAL_TIMEOUT if the timeout was reached,
+ *    SIGNAL_ERROR if some error occured
+ */
+int signal_wait(const dnbd3_signal_t* const signal, int timeoutMs);
+
+/**
+ * Clears any pending signals on this signal.
+ * @return number of signals that were pending,
+ *    SIGNAL_ERROR if some error occured
+ */
+int signal_clear(const dnbd3_signal_t* const signal);
+
+/**
+ * Close the given signal.
+ */
+void signal_close(const dnbd3_signal_t* const signal);
+
+/**
+ * Get a file descriptor for the given signal that can be
+ * waited on using poll or similar.
+ * @return -1 if the signal is invalid
+ */
+int signal_getWaitFd(const dnbd3_signal_t* const signal);
+
+#endif