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Lazarus – An IDE for Free Pascal

by Alan German

When searching for information on the Free Pascal Compiler (FPC), I found that most of the hits related to Lazarus, an integrated development environment (IDE) for FPC.

While the standard version of FPC runs in a command window, Lazarus offers a modern, graphical user interface, with multiple display windows for a variety of tasks.

The program is readily downloaded and installed from a single distribution file (I used lazarus-182-fpc-304-win64.exe, the 64-bit version) which installs both FPC and the Lazarus IDE.

By default, Lazarus opens a number of windows, including a source editor, form manager, and an object inspector. For simple programming, we don’t need the form manager or the object inspector so both of these windows can be closed.

Using Lazarus is not particularly intuitive. For example, clearing the source editor window, loading our hello.pas source code (see the previous article in this series, A Free Pascal Compiler), and compiling the code, immediately generates a fatal error – Can’t find unit1 used by Project1. Perhaps we shouldn’t have cleared the “unit1” code from the source editor!

Fortunately, there are some very good on-line tutorials on how to use Lazarus. For example,
Lazarus Pascal Programming Tutorials - Tutorial 1 - Getting Started shows how to use File – New – Program to create a program template. We simply add the writeln ('Hello world'); and readln; commands between the already-established begin and end lines of code.

We can compile the program using Run – Compile and the message window will now indicate “Success”. Alternatively, we can use the run icon (the forward-arrow) on the menu ribbon which will both compile the code and run the executable program that is automatically created. This process also opens a command window in which the program’s output – “Hello world” – is displayed.

So, Lazarus is (at least) one step up from using FPC in its default environment. In the next article in this series, we will see if we can use the IDE to breathe new life into an old Turbo Pascal program.

Bottom Line:

Lazarus (Open Source)
Version 1.8.2
Lazarus Development Team

Originally published: February 2019

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