On the Amiga there are at least two ways to start a program running:

  * By activating a tool or project icon in Workbench (an icon is
    activated by pointing to it with the mouse and double-clicking
    the mouse select button.)

  * By typing the name of an executable file at the Shell (also
    known as the CLI or Command Line Interface)

In the Workbench environment, a program is run as a separate process.  A
process is simply a task with additional information needed to use DOS
library.

By default, a Workbench program does not have a window to which its output
will go.  Therefore, stdin and stdout do not point to legal file handles.
This means you cannot use stdio functions such as printf() if your program
is started from Workbench unless you first set up a stdio window.

Some compilers have options or defaults to provide a stdio window for
programs started from Workbench.  In Release 2, applications can use an
auto console window for stdio when started from Workbench by opening
"CON:0/0/640/200/auto/close/wait" as a file.  An auto console window will
only open if stdio input or output occurs.  This can also be handled in
the startup code module that comes with your compiler.

 argument passing in workbench 
 wbstartup message 
 example of parsing workbench arguments