fix: __STDC_VERSION__ can be undefined in C++

[lttng-ust.git] / include / lttng / ust-compiler.h

diff --git a/include/lttng/ust-compiler.h b/include/lttng/ust-compiler.h
index eb201bdc93c791f142d2cbc0aa7a86fd90d2472d..b7fd2c1c42bff2bac5d6bfc1c4f403a61fa82234 100644 (file)
--- a/include/lttng/ust-compiler.h
+++ b/include/lttng/ust-compiler.h
@@ -68,7 +68,7 @@
 #ifdef __cplusplus
 #define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
        static_assert(predicate, msg)
-#elif __STDC_VERSION__ >= 201112L
+#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
 #define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
        _Static_assert(predicate, msg)
 #else
@@ -86,4 +86,61 @@
     typedef char lttng_ust_static_assert_##c_identifier_msg[2*!!(predicate)-1]
 #endif
 
+/* Combine two tokens. */
+#define LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)                   \
+               _tokena##_tokenb
+#define LTTNG_UST_COMPILER_COMBINE_TOKENS(_tokena, _tokenb)                    \
+               LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)
+/*
+ * Wrap constructor and destructor functions to invoke them as functions with
+ * the constructor/destructor GNU C attributes when building as C, or as the
+ * constructor/destructor of a variable defined within an anonymous namespace
+ * when building as C++.
+ */
+#ifdef __cplusplus
+#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,       \
+                                                destructor_func, ...)          \
+namespace lttng {                                                              \
+namespace ust {                                                                        \
+namespace details {                                                            \
+class LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_,      \
+                                  name) {                                      \
+public:                                                                                \
+       LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
+       ~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
+};                                                                             \
+LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
+{                                                                              \
+       constructor_func();                                                     \
+}                                                                              \
+LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
+{                                                                              \
+       destructor_func();                                                      \
+}                                                                              \
+}                                                                              \
+}                                                                              \
+}                                                                              \
+                                                                               \
+namespace {                                                                    \
+const lttng::ust::details::LTTNG_UST_COMPILER_COMBINE_TOKENS(                  \
+       lttng_ust_constructor_destructor_, name)                                \
+               LTTNG_UST_COMPILER_COMBINE_TOKENS(name, registration_instance); \
+}
+#else /* __cplusplus */
+#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,       \
+                                                destructor_func, ...)          \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
+               __attribute__((constructor)) __VA_ARGS__;                       \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
+       {                                                                       \
+               constructor_func();                                             \
+       }                                                                       \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
+               __attribute__((destructor)) __VA_ARGS__;                        \
+       static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
+       {                                                                       \
+               destructor_func();                                              \
+       }
+#endif
+
 #endif /* _LTTNG_UST_COMPILER_H */