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mgrigorov pushed a commit to branch branch-1.12
in repository https://gitbox.apache.org/repos/asf/avro.git
The following commit(s) were added to refs/heads/branch-1.12 by this push:
new db5502351a AVRO-4221: [C++] Allow using symbol visibility annotations
also on non-Windows platforms (#3602)
db5502351a is described below
commit db5502351a76d311f9f51ea761298a25fc2637a0
Author: Stephan Lachnit <[email protected]>
AuthorDate: Thu Jan 22 13:27:36 2026 +0100
AVRO-4221: [C++] Allow using symbol visibility annotations also on
non-Windows platforms (#3602)
In GCC and clang the symbol visibility behavior of MSVC can be mirror using
`-fvisibility=hidden`.
This allows to more easily test that symbol visbility annotations work
correctly and can potentially lead to smaller binaries.
The default behavior on non-Windows platforms is not changed with this
commit.
See also https://gcc.gnu.org/wiki/Visibility
Also fixes a tiny mistake where the _WIN32 macro was used to silence a MSVC
warning where the _MSC_VER macro should have been used instead.
---
lang/c++/impl/json/JsonDom.hh | 4 +--
lang/c++/include/avro/Compiler.hh | 4 +--
lang/c++/include/avro/Config.hh | 40 ++++++++++++++++++-------
lang/c++/include/avro/buffer/BufferStream.hh | 4 +--
lang/c++/include/avro/buffer/BufferStreambuf.hh | 4 +--
5 files changed, 38 insertions(+), 18 deletions(-)
diff --git a/lang/c++/impl/json/JsonDom.hh b/lang/c++/impl/json/JsonDom.hh
index 75728c6bad..b2be02b30c 100644
--- a/lang/c++/impl/json/JsonDom.hh
+++ b/lang/c++/impl/json/JsonDom.hh
@@ -31,7 +31,7 @@
namespace avro {
-class AVRO_DECL InputStream;
+class InputStream;
namespace json {
class Entity;
@@ -59,7 +59,7 @@ enum class EntityType {
Obj
};
-const char *typeToString(EntityType t);
+AVRO_DECL const char *typeToString(EntityType t);
inline std::ostream &operator<<(std::ostream &os, EntityType et) {
return os << typeToString(et);
diff --git a/lang/c++/include/avro/Compiler.hh
b/lang/c++/include/avro/Compiler.hh
index bdcbb355e2..7a97c4f4d5 100644
--- a/lang/c++/include/avro/Compiler.hh
+++ b/lang/c++/include/avro/Compiler.hh
@@ -25,14 +25,14 @@
namespace avro {
-class AVRO_DECL InputStream;
+class InputStream;
/// This class is used to implement an avro spec parser using a flex/bison
/// compiler. In order for the lexer to be reentrant, this class provides a
/// lexer object for each parse. The bison parser also uses this class to
/// build up an avro parse tree as the avro spec is parsed.
-class AVRO_DECL ValidSchema;
+class ValidSchema;
/// Given a stream containing a JSON schema, compiles the schema to a
/// ValidSchema object. Throws if the schema cannot be compiled to a valid
diff --git a/lang/c++/include/avro/Config.hh b/lang/c++/include/avro/Config.hh
index dd2438debb..5f5becc0dc 100644
--- a/lang/c++/include/avro/Config.hh
+++ b/lang/c++/include/avro/Config.hh
@@ -19,25 +19,45 @@
#ifndef avro_Config_hh
#define avro_Config_hh
-// Windows DLL support
-
-#ifdef _WIN32
+#ifdef _MSC_VER
#pragma warning(disable : 4275 4251)
+#endif // _MSC_VER
+
+/*
+ * Symbol visibility macros:
+ * - AVRO_DLL_EXPORT annotation for exporting symbols
+ * - AVRO_DLL_IMPORT annotation for importing symbols
+ * - AVRO_DLL_HIDDEN annotation for hiding symbols
+ * - AVRO_DYN_LINK needs to be defined when compiling / linking avro as
dynamic library
+ * - AVRO_SOURCE needs to be defined when compiling avro as library
+ * - AVRO_DECL contains the correct symbol visibility annotation depending on
AVRO_DYN_LINK and AVRO_SOURCE
+ */
+
+#if defined _WIN32 || defined __CYGWIN__
+#define AVRO_DLL_EXPORT __declspec(dllexport)
+#define AVRO_DLL_IMPORT __declspec(dllimport)
+#define AVRO_DLL_HIDDEN
+#else
+#define AVRO_DLL_EXPORT [[gnu::visibility("default")]]
+#define AVRO_DLL_IMPORT [[gnu::visibility("default")]]
+#define AVRO_DLL_HIDDEN [[gnu::visibility("hidden")]]
+#endif // _WIN32 || __CYGWIN__
-#if defined(AVRO_DYN_LINK)
+#ifdef AVRO_DYN_LINK
#ifdef AVRO_SOURCE
-#define AVRO_DECL __declspec(dllexport)
+#define AVRO_DECL AVRO_DLL_EXPORT
#else
-#define AVRO_DECL __declspec(dllimport)
+#define AVRO_DECL AVRO_DLL_IMPORT
#endif // AVRO_SOURCE
#endif // AVRO_DYN_LINK
-#include <intsafe.h>
-using ssize_t = SSIZE_T;
-#endif // _WIN32
-
#ifndef AVRO_DECL
#define AVRO_DECL
#endif
+#ifdef _WIN32
+#include <intsafe.h>
+using ssize_t = SSIZE_T;
+#endif // _WIN32
+
#endif
diff --git a/lang/c++/include/avro/buffer/BufferStream.hh
b/lang/c++/include/avro/buffer/BufferStream.hh
index a8510adaa1..3aeda37f0f 100644
--- a/lang/c++/include/avro/buffer/BufferStream.hh
+++ b/lang/c++/include/avro/buffer/BufferStream.hh
@@ -35,7 +35,7 @@ namespace avro {
*
**/
-class AVRO_DECL ostream : public std::ostream {
+class ostream : public std::ostream {
public:
/// Default constructor, creates a new OutputBuffer.
@@ -65,7 +65,7 @@ protected:
*
**/
-class AVRO_DECL istream : public std::istream {
+class istream : public std::istream {
public:
/// Constructor, requires an InputBuffer to read from.
diff --git a/lang/c++/include/avro/buffer/BufferStreambuf.hh
b/lang/c++/include/avro/buffer/BufferStreambuf.hh
index 42eb20c21c..38cc91fce6 100644
--- a/lang/c++/include/avro/buffer/BufferStreambuf.hh
+++ b/lang/c++/include/avro/buffer/BufferStreambuf.hh
@@ -41,7 +41,7 @@ namespace avro {
* but we have no need since all writes are immediately stored in the buffer.
**/
-class AVRO_DECL ostreambuf : public std::streambuf {
+class ostreambuf : public std::streambuf {
public:
/// Default constructor creates a new OutputBuffer.
@@ -86,7 +86,7 @@ private:
*
**/
-class AVRO_DECL istreambuf : public std::streambuf {
+class istreambuf : public std::streambuf {
public:
/// Default constructor requires an InputBuffer to read from.
