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Walkthrough: Creating and Using a Static Library
In this walkthrough, you will create a static library (LIB) containing useful routines that can be used by other applications. Using static libraries is a great way to reuse code. Rather than re-implementing these routines in every program you create, you write them once and reference them from applications that need the functionality.
This walkthrough uses native C++. For a walkthrough using native C++ to create a dynamic link library (DLL), see Walkthrough: Creating and Using a Dynamic Link Library. For a walkthrough using Visual C++ that targets the Common Language Runtime, see Walkthrough: Creating and Using a Managed Assembly.
This walkthrough covers the following:
-
Creating a new static library project
-
Adding a class to the static library
-
Creating an application that references the static library
-
Using the functionality from the static library in the console application
-
Running the application
PrerequisitesThis topic assumes you understand the fundamentals of the C++ language.
To create a new static library project
-
From the Project types pane, under Visual C++, select Win32.
To add a class to the static library
-
// MathFuncsLib.h
namespace MathFuncs
{
class MyMathFuncs
{
public:
// Returns a + b
static double Add(double a, double b);
// Returns a - b
static double Subtract(double a, double b);
// Returns a * b
static double Multiply(double a, double b);
// Returns a / b
// Throws DivideByZeroException if b is 0
static double Divide(double a, double b);
};
} // MathFuncsLib.cpp
// compile with: /c /EHsc
// post-build command: lib MathFuncsLib.obj
#include "MathFuncsLib.h"
#include <stdexcept>
using namespace std;
namespace MathFuncs
{
double MyMathFuncs::Add(double a, double b)
{
return a + b;
}
double MyMathFuncs::Subtract(double a, double b)
{
return a - b;
}
double MyMathFuncs::Multiply(double a, double b)
{
return a * b;
}
double MyMathFuncs::Divide(double a, double b)
{
if (b == 0)
{
throw new invalid_argument("b cannot be zero!");
}
return a / b;
}
}
NoteIf building from the command line, you must build the program in two steps. First, compile the code using Cl.exe with the /c compiler option (cl /c /EHsc MathFuncsLib.cpp). This will create an object file named MathFuncsLib.obj. For more information, see /c (Compile Without Linking). Second, link the code using the Library Manager Lib.exe (lib MathFuncsLib.obj). This will create the static library MathFuncsLib.lib. For more information on the Library Manager, see LIB Reference.
To create an application that references the static library
To use the functionality from the static library in the console application
To use the math routines that were created in the static library, you must reference it. To do this, select References… from the Project menu. From the Property Pages dialog, expand the Common Properties node and select References. Then select the Add New Reference… button. For more information on the References… dialog, see References, Common Properties, <Projectname> Property Pages Dialog Box.
The Add Reference dialog is displayed. This dialog lists all the libraries that you can reference. The Project tab lists all the projects in the current solution and any libraries they contain. From the Projects tab, select MathFuncsLib. Then select OK. For more information on the Add Reference dialog, see Add Reference Dialog Box.
To reference the header files of the static library, you must modify the include directories path. To do this, from the Property Pages dialog, expand the Configuration Properties node, then the C/C++ node, and select General. Next to Additional Include Directories, type in the path to the location of the MathFuncsLib.h header file.
You can now use the MyMathFuncs class in this application. Replace the contents of MyExecRefsLib.cpp with the following code:
// MyExecRefsLib.cpp
// compile with: /EHsc /link MathFuncsLib.lib
#include <iostream>
#include "MathFuncsLib.h"
using namespace std;
int main()
{
double a = 7.4;
int b = 99;
cout << "a + b = " <<
MathFuncs::MyMathFuncs::Add(a, b) << endl;
cout << "a - b = " <<
MathFuncs::MyMathFuncs::Subtract(a, b) << endl;
cout << "a * b = " <<
MathFuncs::MyMathFuncs::Multiply(a, b) << endl;
cout << "a / b = " <<
MathFuncs::MyMathFuncs::Divide(a, b) << endl;
return 0;
}Build the executable by selecting Build Solution from the Build menu.
To run the application
Make sure MyExecRefsLib is selected as the default project. From the Solution Explorer, select MyExecRefsLib, and then select Set As StartUp Project from the Project menu.
To run the project, select Start Without Debugging from the Debug menu. The output should look like this:
a + b = 106.4
a - b = -91.6
a * b = 732.6
a / b = 0.0747475
Release έκδοση:
Debug έκδοση:
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