Added placement new comment and new version

Grzegorz Jabłoński
1 parent f39aa06c
Showing 3 changed files with 24 additions and 2 deletions
examples11/02-new/makefile
examples11/02-new/placementnew.cpp
examples11/02-new/placementnew2.cpp
-all: newhandler placementnew placement2 placement3
+all: newhandler placementnew placement2 placementnew2
  
 newhandler: newhandler.o
 	g++ -g -Wall -pedantic $^ -o $@
@@ -12,6 +12,12 @@ placementnew: placementnew.o
 placemenetnew.o: placementnew.cpp
 	g++ -g -c -Wall -pedantic $< -o $@
  
+placementnew2: placementnew2.o
+	g++ -g -Wall -pedantic $^ -o $@
+
+placemenetnew2.o: placementnew2.cpp
+	g++ -g -c -Wall -pedantic $< -o $@
+
 placement2: placement2.o
 	g++ -g -Wall -pedantic $^ -o $@
  
@@ -21,4 +27,4 @@ placement2.o: placement2.cpp
 .PHONY: clean
  
 clean:
-	-rm newhandler.o newhandler placementnew.o placementnew placement2.o placement2
 \ No newline at end of file
+	-rm newhandler.o newhandler placementnew.o placementnew placement2.o placement2 placementnew2.o placementnew2
 \ No newline at end of file
@@ -8,6 +8,7 @@ main ()
 {
   char buf[sizeof (string)];
   string *s = new (buf) string;	// construct an string at .buf;. invokes: operator new(sizeof(string),buf);
+                                // actually undefined behaviour - alignment restrictions might not be fulfilled
   *s = "hello";
   cout << *s << endl;
   s->~string();
+#include  <new>
+#include <string>
+#include <iostream>
+using namespace std;
+
+int
+main ()
+{
+  std::aligned_storage_t<sizeof(string), alignof(string)> buf;
+  string *s = new (&buf) string;	// construct an string at .buf;. invokes: operator new(sizeof(string),buf);
+                                // actually undefined behaviour - alignment restrictions might not be fulfilled
+  *s = "hello";
+  cout << *s << endl;
+  s->~string();
+};