test04.cpp

chronolaw · chronolaw · commit d42381fe6ef3 · 2020-01-17T16:43:35.000+08:00
diff --git a/section1/test04.cpp b/section1/test04.cpp
@@ -0,0 +1,59 @@
+// Copyright (c) 2020 by Chrono
+//
+// g++ test04.cpp -Wall -Werror -std=c++11 -o a.out;./a.out
+// g++ test04.cpp -Wall -Werror -std=c++14 -o a.out;./a.out
+//
+// g++ test04.cpp -DNDEBUG -std=c++11 -o a.out;./a.out
+//
+// gcc -E -dM - < /dev/null
+
+#include <iostream>
+
+//[[deprecated]]      // c+14 or later
+//[[gnu::deprecated]] // c+11 or later
+int old_func()
+{
+    //[[gnu::deprecated]]
+    int value = 0;
+
+    return value;
+}
+
+[[gnu::constructor]]
+void first_func()
+{
+    // can not use cout!
+    printf("before main()\n");
+}
+
+[[gnu::destructor]]
+void last_func()
+{
+    // can not use cout!
+    printf("after main()\n");
+}
+
+void case1()
+{
+    using namespace std;
+
+    [[gnu::unused]]
+    int nouse;
+
+    cout << "case1" << endl;
+}
+
+void case2()
+{
+    using namespace std;
+
+    cout << "case2" << endl;
+}
+
+int main()
+{
+    //old_func();
+
+    case1();
+    case2();
+}
