Index: /trunk/MagicSoft/Mars/mbase/MString.cc
===================================================================
--- /trunk/MagicSoft/Mars/mbase/MString.cc	(revision 4079)
+++ /trunk/MagicSoft/Mars/mbase/MString.cc	(revision 4079)
@@ -0,0 +1,83 @@
+/*====================================================================== *\
+!
+! *
+! * This file is part of MARS, the MAGIC Analysis and Reconstruction
+! * Software. It is distributed to you in the hope that it can be a useful
+! * and timesaving tool in analysing Data of imaging Cerenkov telescopes.
+! * It is distributed WITHOUT ANY WARRANTY.
+! *
+! * Permission to use, copy, modify and distribute this software and its
+! * documentation for any purpose is hereby granted without fee,
+! * provided that the above copyright notice appear in all copies and
+! * that both that copyright notice and this permission notice appear
+! * in supporting documentation. It is provided "as is" without express
+! * or implied warranty.
+! *
+!
+!
+!   Author(s): Thomas Bretz, 3/2004 <mailto:tbretz@astro.uni-wuerzburg.de>
+!
+!   Copyright: MAGIC Software Development, 2000-2004
+!
+!
+\* ======================================================================== */
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// MString
+// =======
+//
+// If you are using root Form() command you must be aware of the fact that
+// it uses a global buffer. This buffer is recreated depending on the
+// length which is necessary to form the string. This recreation is not
+// thread safe and it might result in crashes if used in multi-threaded
+// environments.
+//
+// To get around this problem MString implements a Print() member function
+// which form a string like Form does. This formation is done in a
+// internal buffer. Because this buffer must be recreated and
+// deleted each time Print() is called this might be slower than Form().
+// The advantage is, that the buffer is not global and a call to Print()
+// from different threads is safe. However accessing the same
+// M/TString-object must still be locked with a mutex.
+//
+/////////////////////////////////////////////////////////////////////////////
+#include "MString.h"
+
+ClassImp(MString);
+
+// --------------------------------------------------------------------------
+//
+// Thread safe replacement for Form, use it like:
+//
+//  MString string;
+//  string.Print("MyString has %d bytes", 128);
+//
+MString &MString::Print(const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+
+    Int_t n=256;
+
+    char *ret=0;
+
+    while (1)
+    {
+        ret = new char[n+1];
+        Int_t sz = vsnprintf(ret, n, fmt, ap);
+        if (sz<=n)
+            break;
+
+        n *= 2;
+        delete [] ret;
+    };
+
+    va_end(ap);
+
+    *static_cast<TString*>(this) = ret;
+
+    delete [] ret;
+
+    return *this;
+}
Index: /trunk/MagicSoft/Mars/mbase/MString.h
===================================================================
--- /trunk/MagicSoft/Mars/mbase/MString.h	(revision 4079)
+++ /trunk/MagicSoft/Mars/mbase/MString.h	(revision 4079)
@@ -0,0 +1,45 @@
+#ifndef MARS_MString
+#define MARS_MString
+
+#ifndef ROOT_TString
+#include <TString.h>
+#endif
+
+#include <stdio.h>
+#include <stdarg.h>
+
+class MString : public TString
+{
+public:
+    MString &Print(const char *fmt, ...)
+    {
+        va_list ap;
+        va_start(ap, fmt);
+
+        Int_t n=256;
+
+        char *ret=0;
+
+        while (1)
+        {
+            ret = new char[n+1];
+            Int_t sz = vsnprintf(ret, n, fmt, ap);
+            if (sz<=n)
+                break;
+
+            n *= 2;
+            delete [] ret;
+        };
+
+        va_end(ap);
+
+        *static_cast<TString*>(this) = ret;
+
+        delete [] ret;
+
+        return *this;
+    }
+    ClassDef(MString, 1)
+};
+
+#endif