Delphi in a Nutshell

Name

Program Keyword

Syntax

program Name;
Declarations...
Block.

Description

The program keyword begins an application. The file extension for a program’s source file is .dpr (for “Delphi project”).

Tips and Tricks

• Delphi accepts program parameters, for compatibility with standard Pascal, but it ignores them.

• When the program starts, it first runs the initialization sections of all units, then it runs the program’s statement block. After the block ends, the program calls the ExitProc procedure, then runs the finalization section of each unit.

• Initialization sections run in the order of appearance in the program’s uses declaration, traversing each unit’s uses declaration. Finalization sections run in reverse order of the initialization sections. In other words, the first unit listed in the program’s uses declaration is the first unit to be initialized. Then, the first unit’s used units are initialized one at a time, each unit initializing its used units before its initialization code runs.

• The Block can be a simple end statement if the program has no code to run. In that case, immediately after every initialization section runs, the program ends by calling ExitProc and the finalization sections.

Example

program Echo;
// Echo command-line arguments, separated by spaces.
{$AppType Console}
var
  I: Integer;
begin
  if ParamCount > 0 then
    Write(ParamStr(1));
  for I := 2 to ParamCount do
    Write(' ', ParamStr(I));
  WriteLn;
end.

See Also

Asm Keyword, Begin Keyword, ExitProc Variable, Initialization ...