synchronize GTK2 minimum version in docs

[wxWidgets.git] / include / wx / tls.h

diff --git a/include/wx/tls.h b/include/wx/tls.h
index 7846af1e3be75f25648ac3accfe755946fe80034..6886434c007fa34b71d52d5017348f5bf5b8e502 100644 (file)
--- a/include/wx/tls.h
+++ b/include/wx/tls.h
@@ -22,10 +22,13 @@
 #if !wxUSE_THREADS
     #define wxHAS_COMPILER_TLS
     #define wxTHREAD_SPECIFIC_DECL
-// __thread keyword is supported if configure detected it or when using mingw32
-// >= 4.3 which is known to have it too
-#elif defined(HAVE___THREAD_KEYWORD) || \
-        (defined(__MINGW32__) && wxCHECK_GCC_VERSION(4, 3))
+// otherwise try to find the compiler-specific way to handle TLS unless
+// explicitly disabled by setting wxUSE_COMPILER_TLS to 0 (it is 1 by default).
+#elif wxUSE_COMPILER_TLS
+// __thread keyword is not supported correctly by MinGW, at least in some
+// configurations, see http://sourceforge.net/support/tracker.php?aid=2837047
+// and when in doubt we prefer to not use it at all.
+#if defined(HAVE___THREAD_KEYWORD) && !defined(__MINGW32__)
     #define wxHAS_COMPILER_TLS
     #define wxTHREAD_SPECIFIC_DECL __thread
 // MSVC has its own version which might be supported by some other Windows
@@ -33,7 +36,8 @@
 #elif wxCHECK_VISUALC_VERSION(7)
     #define wxHAS_COMPILER_TLS
     #define wxTHREAD_SPECIFIC_DECL __declspec(thread)
-#endif
+#endif // compilers
+#endif // wxUSE_COMPILER_TLS
 
 // ----------------------------------------------------------------------------
 // define wxTLS_TYPE()
@@ -44,7 +48,13 @@
     #define wxTLS_PTR(var) (&(var))
     #define wxTLS_VALUE(var) (var)
 #else // !wxHAS_COMPILER_TLS
-    #ifdef __WXMSW__
+
+    extern "C"
+    {
+        typedef void (*wxTlsDestructorFunction)(void*);
+    }
+
+    #if defined(__WINDOWS__)
         #include "wx/msw/tls.h"
     #elif defined(__OS2__)
         #include "wx/os2/tls.h"
@@ -60,6 +70,14 @@
     // wxTlsValue<T> represents a thread-specific value of type T but, unlike
     // with native compiler thread-specific variables, it behaves like a
     // (never NULL) pointer to T and so needs to be dereferenced before use
+    //
+    // Note: T must be a POD!
+    //
+    // Note: On Unix, thread-specific T value is freed when the thread exits.
+    //       On Windows, thread-specific values are freed later, when given
+    //       wxTlsValue<T> is destroyed.  The only exception to this is the
+    //       value for the main thread, which is always freed when
+    //       wxTlsValue<T> is destroyed.
     template <typename T>
     class wxTlsValue
     {
@@ -67,32 +85,17 @@
         typedef T ValueType;
 
         // ctor doesn't do anything, the object is created on first access
-        //
-        // FIXME: the thread-specific values are currently not freed under
-        //        Windows, resulting in memory leaks, this must be implemented
-        //        there somehow (probably by keeping a list of all TLS objects
-        //        and cleaning them up in wxThread cleanup)
-        wxTlsValue()
-#if !defined(__OS2__) && defined(__UNIX__)
-            : m_key(free)
-#endif
-        {
-        }
+        wxTlsValue() : m_key(free) {}
 
         // dtor is only called in the main thread context and so is not enough
         // to free memory allocated by us for the other threads, we use
         // destructor function when using Pthreads for this (which is not
         // called for the main thread as it doesn't call pthread_exit() but
-        // just to be safe we also reset the key anyhow) and simply leak the
-        // memory under Windows (see the FIXME above)
+        // just to be safe we also reset the key anyhow)
         ~wxTlsValue()
         {
-            void * const value = m_key.Get();
-            if ( value)
-            {
-                free(value);
-                m_key.Set(NULL);
-            }
+            if ( m_key.Get() )
+                m_key.Set(NULL); // this deletes the value
         }
 
         // access the object creating it on demand
@@ -133,7 +136,7 @@
     };
 
     #define wxTLS_TYPE(T) wxTlsValue<T>
-    #define wxTLS_PTR(var) (var)
+    #define wxTLS_PTR(var) ((var).Get())
     #define wxTLS_VALUE(var) (*(var))
 #endif // wxHAS_COMPILER_TLS/!wxHAS_COMPILER_TLS