HELP CHARIN                                        A. Sloman August 1990

    charin() -> character

This procedure reads a character from the user's terminal, or in VED's
immediate mode from the current VED buffer. More precisely, it reads
from the device * pop_charin_device, described in REF * SYSIO.

For full details concerning CHARIN, see REF * CHARIO/charin

See HELP *ASCII for character codes.

CHARIN normally returns an ASCII character code, but when the character
typed at the terminal is the "end of file" character, it returns the
POP11 terminator object TERMIN. (See HELP * TERMIN).

If the last character read in was a newline, then CHARIN will print a
prompt at the terminal. The prompt is in the string * POPPROMPT, and can
be changed by the user.

Warning: if the character typed at the beginning of a line is a
character in the list pop_charin_escapes, then the remainder of the line
is given as a SHELL or DCL command to a sub-process. This can be
prevented by putting in your init.p file

    [] -> pop_charin_escapes

Unlike RAWCHARIN, CHARIN will not produce a result until the user has
typed a 'break' character, e.g. <CR>, or <ESC> or the end of file
character.

The procedure *RAWCHARIN is used by the VED editor and other utilities
to read characters from the terminal in 'raw' mode. In this mode there
is no prompt, the characters are not echoed, and there is no conversion
of the end-of-file character to TERMIN.

See also

REF *SYSIO       - for more information on Input/Output procedures
REF *CHARIO      - on character streams
HELP *CUCHARIN   - variable holding character repeater currently in use
HELP *RAWCHARIN  - for input in "raw" mode
HELP *ASCII      - on character codes in POP_11
HELP *CHAROUT    - outputs a character to the user's terminal
HELP *INCHARITEM - converts a character repeater to an item repeater
HELP *DISCIN     - creates a character repeater for a file or device
HELP *CHARIN_TIMEOUT
                 - read a character, but return false if nothing is
                   typed within a specified time.

--- C.all/help/charin
--- Copyright University of Sussex 1990. All rights reserved. ----------
