The goal of this assignment is to understand the concepts and to learn how to create and use dynamic link libraries in
95/98/NT/w2k environment. A good description of the related system services is given in "Win32 System Services” by
Marshall Brain (pages 741 through 752 2nd edition, 585-598 3rd edition).
The assignment has three parts:
PART A - Create a static library
A1. Create source files x.cpp and x.h which implement the functions:
double add(double a, double b); // Add two doubles
double sub(double a, double b); // Subtract two doubles (a-b)
and source files y.cpp and y.h which implement the functions:
double mul(double a, double b); // Multiply two doubles
double divide(double a, double b, int* err); // Divide two doubles (a/b)
Operand err is a pointer to an error code which has value 1 in case the second operand has the magnitude less than
0.1e-10, otherwise err is set to 0. Be sure you supply the extern "C" statements in x.h and y.h.
A2. Use the files x.cpp and y.cpp to create two static libraries xs.lib and ys.lib.
A3. Write the main program (p11.cpp), which prompts the user to enter two doubles, then computes their sum,
difference, product and quotient, using the library functions specified above. The output results should be accompanied
by proper labels (like: "The sum of a and b is: "). Also, in case of division, the program is checking the error code and
is issuing an error message if the division wasn't completed successfully. The program should repeat the prompt-enter-
compute cycle as long there are valid data present at the standard input. If anything different than numbers is presented
at the input, the program should exit with a proper error message.
A4. For compilation, creation of libraries and for linking use commands cl, lib, and link respectively. You may do
the job by using a simple (commented!) batch file (p11.bat), or a (commented) make file (p11.mak).
Instruction what to turn in is given at the end of this file.
PART B - Create a dynamic link library (linked at load time)
B1. Use x.obj and y.obj to create libraries x.dll and y.dll. For this you need to supply the definition files
x.def and y.def.
B2. Using link command create p12.exe which can be dynamically linked with x.dll and y.dll at load time.
For this use the same source file p11.cpp from the part A.
B3. After you have created all dll and exe files, rename one of the dll files and try to run p12.exe. See what will
happen.
B4. Return the correct name to the renamed dll file and run p12.exe again. This time you should get successful
loading and execution.
B5. Change one of the library sources. For example you may change the comments in x.cpp (e.g. add comment:
CS570 Operating Systems Spring 2004
Programming Assignment #1 Assigned: January 26 Due: February 4
