1. Introduction
  2. Structure
  3. Packaging
  4. Logging
  5. Configuration
  6. Debugging EXEs
  7. Handling errors
  8. Testing
  9. Documentation
  10. Make
  11. Providing help
  12. Scheduled Tasks
  13. Windows Services
  14. Windows Event Log
  15. Windows Registry
  16. Creating SetUp.exe
  17. Regular Expressions
  18. Acre
  19. GUI
  20. Git


  1. Windows environment vars
  2. User commands
  3. aplcores & WS integrity
  4. Development environment
  5. Special characters
  6. The current directory


The current directory, sometimes also referred to as working directory — or even starting working directory — as well as Start in" in some dialog boxes is an important concept: it's where a file without a path name will be searched for

Double-clicking a Dyalog EXE

The EXE's installation path is the current directory.

Calling a Dyalog EXE or a DYAPP from a console window

The current directory of the console window is also going to be the EXE's current directory.

Double-clicking DWS or DYAPP

The current directory is going to be where the workspace or the DYAPP file lives.

Double-clicking a shortcut

The result depends on whether a folder is specified in “Start in” (available via the shortcut's “Properties” dialog):

– If “Start in” specifies a valid folder then this will determine the current directory.

– If “Start in” is empty or specifies an invalid folder[1] then the folder the shortcut lives in will determine the current directory.


Normally when a program is started the folder the EXE lives in determines the current directory.

This is also true when you call any Dyalog EXE. However, from an APL programmer's point of view the workspace defines the program, not the EXE. That's why we advocate changing the current directory to where the workspace was loaded from.

⍝TODO⍝ This is currently not true:

It's similar for DYAPPs, though they don't load a workspace but assemble it dynamically. In case of a double-click on a DYAPP luckily there is no need to do anything because the current directory will be the folder the DYAPP lives in, which is exactly how it should be.

⍝TODO⍝: we need a mechanism for DYAPPs in case they got called programmitically!


  1. Although it is impossible to enter an invalid path in the “Properties” dialog of a shortcut, a valid folder name might of course become invalid at a later point.