substring method

include/amsstring4/amsstring4.hpp

@@ -93,6 +93,7 @@ public:
     void remove(const int ind);
     void remove(const int ind1, const int ind2);
     void substring(const int ind1, const int ind2, amsstring *sout) const;
+    amsstring substring(const int ind1, const int ind2) const;
 
     //Append
     void append(const amsstring &other);

src/amsstring4/amsstring4_class.cpp

@@ -654,6 +654,13 @@ namespace ams
       return;
     }
 
+    amsstring amsstring::substring(const int ind1, const int ind2) const
+    {
+      amsstring ret;
+      this->substring(ind1,ind2,&ret);
+      return ret;
+    }
+    
     void amsstring::append(const amsstring &other)
     {
       this->insert(this->length,other);

src/amsstring4/amsstring4_portability.cpp

@@ -140,7 +140,7 @@ int amssprintf_s(char *s, int n, const char *format, ...)
   //va_arg(val,datatype)
   // if(s!=NULL)
   // {
-    #if defined(LINUX) || defined(linux) || defined(__linux__) || defined(__GNUC__)
+    #if defined(LINUX) || defined(linux) || defined(__linux__) || defined(__GNUC__) || defined(__APPLE__) || defined(__MACH__)
         //use snprintf
         ret = (int)vsnprintf(s,n,format,args);
         s[n-1] = '\0';