Environment > Setting Preferences > General User Environment Preferences

# General User Environment Preferences

This section describes the preferences for the general user environment.

## IDL_DATAFILE_USER_COMMENTS

The IDL_DATAFILE_USER_COMMENTS preference specifies whether or not IDL is allowed to put comments that include user and host name into generated data files, such as SAVE and JOURNAL files. Such comments are usually considered to be helpful in most environments, but can be a problem for those working in secure environments with specific rules governing the information that is allowed to leave a given security level.

Value | Aliases
0 | False, No, Off
1 | True, Yes, On

Committed changes take effect immediately. The default value is True (1).

This preference can be set in the IDL Workbench Preferences dialog.

## IDL_DEVICE

IDL’s direct graphics system always operates on the current graphics device, which you can change with the SETENV procedure. The IDL_DEVICE preference specifies the initial graphics device that starts out as current.

Committed changes take effect at the next `.reset_session` executive command or in future IDL sessions. The default value is the window system supported by IDL for the target platform: “X” for UNIX systems and “WIN” for Microsoft Windows.

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_EDIT_INPUT

The IDL_EDIT_INPUT preference sets the initial value of the !EDIT_INPUT system variable, which determines whether or not the tty-based (non-IDE) command-line version of IDL does command-line editing when reading commands. For related information on the command recall buffer, see IDL_RBUF_PERSIST and IDL_RBUF_SIZE.

Value | Aliases
0 | False, No, Off
1 | True, Yes, On

Committed changes take effect immediately. The default value is True (1).

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_EXCEPT

The IDL_EXCEPT preference sets the initial value of the !EXCEPT system variable, which controls when IDL checks for invalid mathematical computations (exceptions).

Value | Aliases
0 | Never, No
1 | OnInterpreterHalt, Halt
2 | AfterStmt, Stmt

Committed changes take effect immediately. The default value is OnInterpreterHalt (1).

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_MORE

The IDL_MORE preference sets the initial value of the !MORE system variable, which controls whether IDL should paginate help output sent to a TTY device. This preference has no effect on the IDL Workbench Console view.

Value | Aliases
0 | False, No, Off
1 | True, Yes, On

Committed changes take effect immediately. The default value is True (1).

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_MSG_PREFIX

The IDL_MSG_PREFIX preference sets the value of the !ERROR_STATE.MSG_PREFIX system variable, which determines the prefix string used for error messages.

Committed changes take effect immediately. The default value is `'% '`.

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_PROMPT

The IDL_PROMPT preference sets the value of the !PROMPT system variable, which contains the text string that IDL uses to prompt for input.

Committed changes take effect immediately. The default value is `'IDL> '`.

This preference can be set in the IDL Workbench Preferences dialog.

## IDL_QUIET

The IDL_QUIET preference sets the value of the !QUIET system variable, which controls whether informational messages are printed (value is 0) or suppressed (1).

Value | Aliases
0 | False, No, Off
1 | True, Yes, On

Committed changes take effect immediately. The default value is False (0).

This preference cannot be set in the IDL Workbench Preferences dialog.

## IDL_RBUF_PERSIST

The IDL_RBUF_PERSIST preference determines whether the IDL command recall buffer is saved between IDL sessions. For related information on the recall buffer, see IDL_EDIT_INPUT and IDL_RBUF_SIZE.

Value | Aliases
0 | False, No, Off
1 | True, Yes, On

Committed changes take effect immediately. The default value is True (1).

This preference can be set in the IDL Workbench Preferences dialog.

## IDL_RBUF_SIZE

The IDL_RBUF_SIZE preference sets the size of the IDL command recall buffer. It must be set to a value greater than or equal to 1. For related information on the recall buffer, see IDL_EDIT_INPUT and IDL_RBUF_PERSIST.

Committed changes take effect immediately. The default value is 500.

This preference can be set in the IDL Workbench Preferences dialog.