Add context info when reporting plugin error loading

src/plugin/PlugInBase.cpp

@@ -41,6 +41,7 @@
 // DEPENDENCIES
 // ============================================================================
 #include <iostream>
+#include <yat/utils/String.h>
 #include <yat/plugin/PlugIn.h>
 #include <yat/plugin/PlugInSymbols.h>
 #include <yat/plugin/IPlugInObjectWithAttr.h>
@@ -80,7 +81,8 @@ PlugInBase::Symbol PlugInBase::find_symbol(const std::string &symbol)
   }
 
   THROW_YAT_ERROR("SHAREDLIBRARY_ERROR",
-                  "Unable to find the requested symbol",
+          SFormat("Unable to find the requested symbol '{}'"
+                  " while loading library file {}") % symbol % m_libraryName,
                   "PlugInBase::find_symbol");
   return NULL;    // keep compiler happy
 }