#NoEnv [v1.0.43.08+]
Avoids checking empty variables to see if they are environment variables (recommended for all new scripts).
#NoEnv
Specifying the line #NoEnv anywhere in a script prevents empty variables from being looked up as potential environment variables. For example:
#NoEnv MsgBox %WinDir%
The above would not retrieve the "WinDir" environment variable (though that could be solved by doing WinDir := A_WinDir near the top of the script).
Specifying #NoEnv is recommended for all new scripts because:
- It significantly improves performance whenever empty variables are used in an expression or command. It also improves DllCall's performance when unquoted parameter types are used (e.g. int vs. "int").
- It prevents script bugs caused by environment variables whose names unexpectedly match variables used by the script.
- AutoHotkey v2 will make this behavior the default.
To help ease the transition to #NoEnv, the built-in variables Comspec and ProgramFiles have been added. They contain the same strings as the corresponding environment variables.
When #NoEnv is in effect, the script should use EnvGet to retrieve environment variables, or use built-in variables like A_WinDir.