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authorWillem Jan Palenstijn <wjp@usecode.org>2016-05-17 17:19:31 +0200
committerWillem Jan Palenstijn <wjp@usecode.org>2016-05-17 17:19:31 +0200
commit844a9f71fba18c76d6b3566b78908877a0a1a9c8 (patch)
treeadb88053a6e68003ff57dd2dfc8dc6d07b728aa5 /include/astra/Singleton.h
parentd60df8bbd0e17016036c279720d6e3464a4d295c (diff)
parentf9b68bafd90941d9faf53e5e2771361e3ab4336a (diff)
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Merge pull request #55 from wjp/singleton_construction
Avoid defining singleton construction in header file
Diffstat (limited to 'include/astra/Singleton.h')
-rw-r--r--include/astra/Singleton.h22
1 files changed, 18 insertions, 4 deletions
diff --git a/include/astra/Singleton.h b/include/astra/Singleton.h
index a256187..784c521 100644
--- a/include/astra/Singleton.h
+++ b/include/astra/Singleton.h
@@ -57,15 +57,17 @@ class Singleton {
m_singleton = 0;
}
+ static void construct();
+
// get singleton
static T& getSingleton() {
if (!m_singleton)
- m_singleton = new T();
+ construct();
return *m_singleton;
}
static T* getSingletonPtr() {
if (!m_singleton)
- m_singleton = new T();
+ construct();
return m_singleton;
}
@@ -76,11 +78,23 @@ class Singleton {
};
-#define DEFINE_SINGLETON(T) template<> T* Singleton<T >::m_singleton = 0
+// We specifically avoid defining construct() in the header.
+// That way, the call to new is always executed by code inside libastra.
+// This avoids the situation where a singleton gets created by a copy
+// of the constructor linked into an object file outside of libastra, such
+// as a .mex file, which would then also cause the vtable to be outside of
+// libastra. This situation would cause issues when .mex files are unloaded.
+
+#define DEFINE_SINGLETON(T) \
+template<> void Singleton<T >::construct() { assert(!m_singleton); m_singleton = new T(); } \
+template<> T* Singleton<T >::m_singleton = 0
+
// This is a hack to support statements like
// DEFINE_SINGLETON2(CTemplatedClass<C1, C2>);
-#define DEFINE_SINGLETON2(A,B) template<> A,B* Singleton<A,B >::m_singleton = 0
+#define DEFINE_SINGLETON2(A,B) \
+template<> void Singleton<A,B >::construct() { assert(!m_singleton); m_singleton = new A,B(); } \
+template<> A,B* Singleton<A,B >::m_singleton = 0
} // end namespace