common: add generic input-line interface, and an implementation of it for text files

common/include/ivy/status.h

@@ -0,0 +1,15 @@
+#ifndef IVY_COMMON_STATUS_H_
+#define IVY_COMMON_STATUS_H_
+
+enum ivy_status {
+	IVY_OK = 0,
+	IVY_ERR_EOF = -1,
+	IVY_ERR_IO_FAILURE = -2,
+	IVY_ERR_BAD_SYNTAX = -3,
+	IVY_ERR_NO_MEMORY = -4,
+	IVY_ERR_NOT_SUPPORTED = -5,
+};
+
+extern const char *ivy_status_to_string(enum ivy_status status);
+
+#endif