From 7f04d825cea33617f85ba367f8873ac1f63bbcdc Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@aps.anl.gov>
Date: Tue, 17 Jul 2012 23:41:06 -0500
Subject: [PATCH] Add some missing epicsShareClass decorations.

Also set the gcc-4 visibility attribute in shareLib.h
---
 src/ca/legacy/pcas/generic/casdef.h | 16 ++++++-------
 src/libCom/fdmgr/fdManager.h        |  2 +-
 src/libCom/misc/shareLib.h          | 35 +++++++++++++++++++++++------
 3 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/src/ca/legacy/pcas/generic/casdef.h b/src/ca/legacy/pcas/generic/casdef.h
index 5d1e60981..001f7bb11 100644
--- a/src/ca/legacy/pcas/generic/casdef.h
+++ b/src/ca/legacy/pcas/generic/casdef.h
@@ -150,7 +150,7 @@ private:
 //
 // caServer - Channel Access Server API Class
 //
-class caServer {
+class epicsShareClass caServer {
     friend class casPVI;
 public:
     epicsShareFunc caServer ();
@@ -312,7 +312,7 @@ private:
 // then it may decide to provide a "destroy()" implementation in the
 // derived class which is a noop.
 //
-class casPV {
+class epicsShareClass casPV {
 public:
     epicsShareFunc casPV ();
     
@@ -566,7 +566,7 @@ public:
 // occurring when both the server library and the server tool attempt 
 // to destroy the same casChannel derived object at the same instant.
 //
-class casChannel {
+class epicsShareClass casChannel {
 public:
     epicsShareFunc casChannel ( const casCtx & ctx );
     epicsShareFunc virtual ~casChannel ();
@@ -724,7 +724,7 @@ private:
 // in the destructor, for the class deriving from 
 // casAsyncReadIO.
 // **
-class casAsyncReadIO {
+class epicsShareClass casAsyncReadIO {
 public:
 
     //
@@ -784,7 +784,7 @@ private:
 // casAsyncWriteIO.
 // **
 //
-class casAsyncWriteIO {
+class epicsShareClass casAsyncWriteIO {
 public:
     //
     // casAsyncWriteIO()
@@ -830,7 +830,7 @@ private:
 // casAsyncPVExistIO 
 // - for use with caServer::pvExistTest()
 //
-class casAsyncPVExistIO {
+class epicsShareClass casAsyncPVExistIO {
 public:
 
     //
@@ -879,7 +879,7 @@ private:
 // casAsyncPVAttachIO 
 // - for use with caServer::pvAttach()
 //
-class casAsyncPVAttachIO {
+class epicsShareClass casAsyncPVAttachIO {
 public:
     //
     // casAsyncPVAttachIO()
@@ -926,7 +926,7 @@ private:
 // casAsyncPVCreateIO (deprecated)
 // (this class will be deleted in a future release)
 //
-class casAsyncPVCreateIO : private casAsyncPVAttachIO {
+class epicsShareClass casAsyncPVCreateIO : private casAsyncPVAttachIO {
 public:
     epicsShareFunc casAsyncPVCreateIO ( const casCtx & ctx );
     epicsShareFunc virtual ~casAsyncPVCreateIO ();
diff --git a/src/libCom/fdmgr/fdManager.h b/src/libCom/fdmgr/fdManager.h
index 23ca84587..6bcd2e557 100644
--- a/src/libCom/fdmgr/fdManager.h
+++ b/src/libCom/fdmgr/fdManager.h
@@ -122,7 +122,7 @@ epicsShareExtern fdManager fileDescriptorManager;
 //
 // file descriptor registration
 //
-class fdReg : public fdRegId, public tsDLNode<fdReg>, public tsSLNode<fdReg> {
+class epicsShareClass fdReg : public fdRegId, public tsDLNode<fdReg>, public tsSLNode<fdReg> {
     friend class fdManager;
 
 public:
diff --git a/src/libCom/misc/shareLib.h b/src/libCom/misc/shareLib.h
index ba23b282f..789ce6b08 100644
--- a/src/libCom/misc/shareLib.h
+++ b/src/libCom/misc/shareLib.h
@@ -29,12 +29,9 @@
  * int epicsShareAPI myExtFunc ( int arg );   
  * int epicsShareAPI myExtFunc ( int arg ) {}
  *
- * ** NOTE **  epicsShareAPI is deprecated for new routines, don't use it!
- *             In a future major release (R3.15) we will remove this keyword
- *             from most EPICS APIs, although CA may continue to use it.
- *             This is a major release though, since it affects the order
- *             that arguments are pushed onto the stack on Windows and we
- *             don't want a replacement DLL to silent cause mayhem...
+ * ** NOTE **  epicsShareAPI is deprecated for new routines and has been removed
+ *             from all IOC-specific APIs, although most libCom APIs are still
+ *             declared to use it.
  *
  * 2) epicsShare{Func,Class,Extern,Def} - specifies shareable library (DLL) 
  * export/import related information in the source code. On windows these keywords 
@@ -44,7 +41,11 @@
  * names. These keywords are only necessary if the address of a function or data 
  * internal to a shareable library (DLL) needs to be visible outside of this shareable 
  * library (DLL). All compilers targeting windows accept the __declspec(dllexport)
- * and __declspec(dllimport) keywords.
+ * and __declspec(dllimport) keywords. For GCC version 4 and above the first three
+ * keywords specify a visibility attribute of "default", which marks the symbol as
+ * exported even when gcc is given the option -fvisibility=hidden. Doing this can
+ * significantly reduce the number of symbols exported to a shared library. See the
+ * URL below for more information.
  *
  * In header files declare references to externally visible variables, classes and 
  * functions like this:
@@ -139,6 +140,26 @@
 #   define epicsShareDef 
 #   define epicsShareAPI __stdcall /* function removes arguments */
 #   define READONLY const
+
+#elif __GNUC__ >= 4
+/*
+ * See http://gcc.gnu.org/wiki/Visibility
+ * For these to have any effect, the compiler and linker must be given the flag
+ *     -fvisibility=hidden
+ */
+
+#   define epicsShareExtern __attribute__ ((visibility("default"))) extern
+#   define epicsShareClass __attribute__ ((visibility("default")))
+#   define epicsShareFunc __attribute__ ((visibility("default")))
+
+#   define epicsShareDef
+#   define epicsShareAPI
+#   if defined(__STDC__) || defined (__cplusplus)
+#       define READONLY const
+#   else
+#       define READONLY
+#   endif
+
 /*
  * if its the old VAX C Compiler (not DEC C)
  */