HP C/aC++ for PA-RISC Software manual ++ Template Tutorial, Class Templates

For example, when your archive library is linked with an application, library objects in the link may be different than those used when linking the library in a prior release.

Following are two examples of building an archive library; one built with

+inst_auto/+inst_close (the prior default), and the other built with the current (compile-time) default:

Building an Archive Library with +inst_auto/+inst_close

Suppose for lib.inst_auto.a, the linker chooses foo2.o to resolve symbol x, and foo3.o to resolve symbol stack <int>, symbols x, y, and stack <int> are each resolved with no duplicates.

lib.inst_auto.a

-------------------------------------------------

foo.o		foo2.o		foo3.o
					stack<int>
	x		x		y
	y

-------------------------------------------------

Building an Archive Library with Compile-time Instantiation

Suppose for lib.default.a, the linker chooses foo2.o to resolve symbol x, and foo.o to resolve symbol stack <int>, symbols x, y, and stack <int> are each resolved, but now there’s a duplicate definition of symbol x. This will cause a linker duplicate symbol error. This is really a user error, but was not visible before.

lib.default.a

-------------------------------------------------

foo.o		foo2.o		foo3.o
	stack<int>		stack<int>		stack<int>
	x		x		y
	y

-------------------------------------------------

NOTE: This example is not meant to account for all cases of changed behavior.

C++ Template Tutorial

You can create class templates and function templates. A template defines a group of classes or functions. A template can have one or more types as parameters. When you use a template, you provide the particular types or constant expressions as actual parameters thereby creating a particular object or function.

Class Templates

A class template defines a family of classes. To declare a class template, you use the keyword template followed by the template’s formal parameters. Class templates can take parameters that are either types or expressions. You define a template class in terms of those parameters. For example, the following is a class template for a simple stack class. The template has two parameters, the type specifier T and the int parameter size. The keyword class in the < > brackets is required to declare any template type parameters. The first parameter T is used for the stack element type. The second parameter is used for the maximum size of the stack.

template<class T, int size> class Stack

{

public: Stack(){top=-1;}

void push(const T& item){thestack[++top]=item;} T& pop(){return thestack[top--];}

private:

T thestack[size];

136 Using HP aC++ Templates