From 7edfc1722684982b9df894c054d69808dc588a6a Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 2 Apr 2020 13:29:45 -0400 Subject: [PATCH] ust-compiler.h: Implement __LTTNG_COMPOUND_LITERAL Implement __LTTNG_COMPOUND_LITERAL to allow defining a compound literal with static storage. Compound literals with static storage are needed by LTTng to implement nested arrays and sequences in TRACEPOINT_EVENT. Compound literals are part of the C99 and C11 standards, but not part of the C++ standards. However, those are supported by both g++ and clang as C99 extensions when compiling C++ code. Strict C++11 compliance can be obtained by defining LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header to allocate those on the heap in C++. Signed-off-by: Mathieu Desnoyers --- include/lttng/ust-compiler.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/include/lttng/ust-compiler.h b/include/lttng/ust-compiler.h index 31eaf73c..799bca42 100644 --- a/include/lttng/ust-compiler.h +++ b/include/lttng/ust-compiler.h @@ -43,4 +43,21 @@ # define __lttng_ust_variable_attribute_no_sanitize_address #endif +/* + * Compound literals with static storage are needed by LTTng. + * Compound literals are part of the C99 and C11 standards, but not + * part of the C++ standards. However, those are supported by both g++ and + * clang. In order to be strictly C++11 compliant, defining + * LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header + * allocates those on the heap in C++. + * + * Example use: + * static struct mystruct *var = __LTTNG_COMPOUND_LITERAL(struct mystruct, { 1, 2, 3 }); + */ +#if defined (__cplusplus) && defined (LTTNG_ALLOCATE_COMPOUND_LITERAL_ON_HEAP) +#define __LTTNG_COMPOUND_LITERAL(type, ...) new (type) __VA_ARGS__ +#else +#define __LTTNG_COMPOUND_LITERAL(type, ...) (type[]) { __VA_ARGS__ } +#endif + #endif /* _LTTNG_UST_COMPILER_H */ -- 2.34.1