read-line (AutoLISP)

Reads a string from the keyboard or from an open file, until an end-of-line marker is encountered

Supported Platforms: Windows, Mac OS, and Web

Signature

(read-line [file-desc])

file-desc

Type: File

A file descriptor (obtained from open) referring to an open file. If no file-desc is specified, read-line obtains input from the keyboard input buffer.

Return Values

Type: String

The text read by read-line, without the end-of-line marker. If read-line encounters the end of the file, it returns nil.

Release Information

Releases:

AutoCAD R12 and later on Windows
AutoCAD 2011 and later on Mac OS

History

AutoCAD 2021

Return value was modified to support Unicode characters and might be different than earlier releases.
LISPSYS system variable controls which AutoLISP engine is used and the behavior of the function.
- 0 - ASCII character support (legacy behavior)
- 1 or 2 - Unicode character support
Note: After the value of the LISPSYS system variable has been changed, AutoCAD must be restarted for the change to take affect.

Examples

Windows

Open a file for reading:

(setq f (open "c:\\my documents\\new.tst" "r"))
#<file "c:\\my documents\\new.tst">

Use read-line to read a line from the file:

(read-line f)
"To boldly go where nomad has gone before."

Obtain a line of input from the user:

(read-line)
To boldly go
"To boldly go"

Mac OS and Web

Open a file for reading:

(setq f (open "/my documents/new.tst" "r"))
#<file "/my documents/new.tst">

Command: