Page 23 - DCAP408_WEB_PROGRAMMING

Unit 1: Windows Programming Basics

If an application has already been formed, to obtain its instance, you can call the Notes
GetWindowLong() function. Its syntax is:

Even though this function is used for many other reasons, it can also aid you get the instance of
an application. To perform this, pass the first argument as the handle to a window of the
application you are probing and pass the second argument as GWL_HINSTANCE.

Self Assessment

Fill in the blank:

14. If an application has already been formed, to obtain its instance, you can call the
........................ function.

1.9 Compiling Windows Program

Click the Run button (displayed below with the arrow) and wait a few seconds. This compiles
the program to an EXE file and runs it:

When the program runs, you will observe the dialog on the screen. It appears like this:

You have effectively written a Windows program that could execute under any version of
Windows. The window above is portion of the EXE file, and it can outside the Developer
Environment if required. Press the “Close me” button to finish the program. The Close button
triggers the Command event, which unloads the dialog. The program will then end since it has
no windows left.
The resource data is stored in separate file in windows programs, compiling a DOS program is
not more involved then the process of putting together a complete Windows program. Figure
1.1 shows that how a C program is run under DOS, how it is being compiled and linked to create
a finished program. Under DOS, the C compiler converts the source code file into an objective
file. A linker converts the objective file into the finished executable program. In this way a
source code can be converted to the finished program with the help of compiler and linker.

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