fix segfault

This patch provides a memory-safe alternative to the changes introduced in commit 418adfde670b8d911a6a313e11a2ee4fc98feeee, which causes a segfault when the "batch mode" flag is required (i.e., for ascii/graphic export).

Note: the program name (i.e., argv[0]) has been added the list arguments passed to ROOT's TApplication. This ensures that the TApplication name matches that of the program (see 542b98b2cc/core/base/src/TApplication.cxx (L179-L180)).

src/musrFT.cpp

@@ -1437,19 +1437,18 @@ Int_t main(Int_t argc, Char_t *argv[])
     musrFT_dumpData(startupParam.dumpFln, fourier, startupParam.fourierRange[0], startupParam.fourierRange[1]);
   } else { // do Canvas
 
-    // if Fourier graphical export is whished, switch to batch mode
+    // if Fourier graphical export is wished, switch to batch mode
     Bool_t batch = false;
-    int cc=0;
+    // create list of essential arguments to pass to the ROOT application
-    char **arg;
+    std::vector<char*> args;
+    args.push_back(argv[0]); // program name
     if (startupParam.graphicFormat.Length() != 0) {
       batch = true;
-      arg[cc] = (Char_t*)malloc(16*sizeof(Char_t));
+      args.push_back((char*)"-b"); // batch mode flag
-      strcpy(arg[cc], "-b");
-      cc++;
     }
-
+    int cc = args.size();
     // plot the Fourier transform
-    TApplication app("App", &cc, arg);
+    TApplication app("App", &cc, args.data());
 
     if (startupHandler) {
       fourierCanvas = std::unique_ptr<PFourierCanvas>(new PFourierCanvas(fourier, dataSetTag, startupParam.title.Data(),

src/musrview.cpp

@@ -37,6 +37,7 @@
 
 #include <iostream>
 #include <memory>
+#include <vector>
 
 #include <TApplication.h>
 #include <TSAXParser.h>
@@ -301,15 +302,15 @@ int main(int argc, char *argv[])
   }
 
   if (result == PMUSR_SUCCESS) {
-    // generate Root application needed for PMusrCanvas
+    // create the ROOT application needed for PMusrCanvas
-    int cc=0;
+    // and pass it only essential arguments
-    char **arg;
+    std::vector<char*> args;
+    args.push_back(argv[0]); // program name
     if (graphicsOutput || asciiOutput) {
-      arg[cc] = (char*)malloc(16*sizeof(char));
+      args.push_back((char*)"-b"); // batch mode flag
-      strcpy(arg[cc], "-b");
-      cc++;
     }
-    TApplication app("App", &cc, arg);
+    int cc = args.size();
+    TApplication app("App", &cc, args.data());
 
     std::vector<PMusrCanvas*> canvasVector;
     PMusrCanvas *musrCanvas;