From c35b0aa270b75127dbabadca7001be60d20f1c47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beat=20K=C3=83=C2=BCng?= <beat-kueng@gmx.net>
Date: Tue, 24 Oct 2017 21:58:48 +0200
Subject: [PATCH] param: redefine type-safe versions for param_get() when used
 in C++ code

---
 src/modules/systemlib/param/param.h | 31 +++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/src/modules/systemlib/param/param.h b/src/modules/systemlib/param/param.h
index 044d893e31..78261bce91 100644
--- a/src/modules/systemlib/param/param.h
+++ b/src/modules/systemlib/param/param.h
@@ -451,4 +451,35 @@ struct param_info_s {
 
 __END_DECLS
 
+
+
+#ifdef	__cplusplus
+#if 0 // set to 1 to debug param type mismatches
+#include <cstdio>
+#define CHECK_PARAM_TYPE(param, type) \
+	if (param_type(param) != type) { \
+		/* use printf() to avoid having to use more includes */ \
+		printf("wrong type passed to param_get() for param %s\n", param_name(param)); \
+	}
+#else
+#define CHECK_PARAM_TYPE(param, type)
+#endif
+
+// param is a C-interface. This means there is no overloading, and thus no type-safety for param_get().
+// So for C++ code we redefine param_get() to inlined overloaded versions, which gives us type-safety
+// w/o having to use a different interface
+static inline int param_get_cplusplus(param_t param, float *val)
+{
+	CHECK_PARAM_TYPE(param, PARAM_TYPE_FLOAT);
+	return param_get(param, val);
+}
+static inline int param_get_cplusplus(param_t param, int32_t *val)
+{
+	CHECK_PARAM_TYPE(param, PARAM_TYPE_INT32);
+	return param_get(param, val);
+}
+#define param_get(param, val) param_get_cplusplus(param, val)
+
+#endif /* __cplusplus */
+
 #endif