Fix missing return statement, add comments

StRoot/StFwdUtils/StFwdAnalysisMaker.h

@@ -25,16 +25,41 @@ class StFwdAnalysisMaker : public StMaker
 
   protected:
 
+    /**
+     * @brief Map of <name (TString), histogram>
+     * 
+     */
     std::map<TString, TH1*> mHists;
+
+    /**
+     * @brief Add a histogram to the map
+     * 
+     * Convenience method to avoid duplicate typing name / possible mismatch
+     * @param h1 TH1* histogram object
+     * @return TH1* return the same object for ease of use
+     */
     TH1 * addHist( TH1 * h1){
       mHists[h1->GetName()] = h1;
+      return h1;
     }
+
+    /**
+     * @brief Get the Hist object from the map
+     *  - Additional check and safety for missing histograms
+     * @param n Histogram name
+     * @return TH1* histogram if found, otherwise a 'nil' histogram with one bin
+     */
     TH1* getHist( TString n ){
       if (mHists.count(n))
         return mHists[n];
       LOG_ERROR << "Attempting to access non-existing histogram" << endm;
       return new TH1F( "NULL", "NULL", 1, 0, 1 ); // returning nullptr can lead to seg fault, this fails softly
     }
+
+    /**
+     * @brief Control whether the analysis uses StEvent (default) or MuDst as input
+     * 
+     */
     bool mAnalyzeMuDst = false;
 
   ClassDef(StFwdAnalysisMaker, 0);