NAME

inkeyS - get a “keystroke”

SYNOPSIS

#include <basic/string.h>

struct string inkeyS()

DESCRIPTION

InkeyS implements the BASIC INKEY$ variable which, apparently, accesses the BIOS code of the IBM PC.  This accounts for the strange behavior of this variable and thus the inkeyS function. 

InkeyS attempts to read a character from the current file (see initio(io)).  This function waits no more than one second for a character or character sequence to arrive (see alarm(io)).  If no character is present, the null string is returned.  If a single character is present, a one character string is allocated and returned.  If a character sequence (or is the null character) is present, inkeyS allocates and returns a two character string consisting of a null character followed by another character code as given in the table below. 

The interpretation of special function keys requires knowledge of the sequences generated by the terminal.  This information is gleaned from the terminal capabilities database which is termcap(5) or terminfo(4), depending on the ancestry of the system.  If a particular sequence for a given terminal is not defined, this function will not recognize the sequence as such.  In this case, The Intrepid Reader who has mustered the audacity to modify the database will find in the table below the i.codes used with termcap and the capnames and term structure names used with terminfo. 

	Code		I.Code		Capname		Term Name		Description
	3		—		—		—		Null character
	58		k0		kf0		key_f0		Function key F0
	59		k1		kf1		key_f1		Function key F1
	60		k2		kf2		key_f2		Function key F2
	61		k3		kf3		key_f3		Function key F3
	62		k4		kf4		key_f4		Function key F4
	63		k5		kf5		key_f5		Function key F5
	64		k6		kf6		key_f6		Function key F6
	65		k7		kf7		key_f7		Function key F7
	66		k8		kf8		key_f8		Function key F8
	67		k9		kf9		key_f9		Function key F9
	68		ka		kf10		key_f10		Function key F10
	71		kh		khome		key_home		Home
	72		ku		kcuu1		key_up		Cursor up
	73		kP		kpp		key_ppage		Page up
	75		kl		kcub1		key_left		Cursor left
	77		kr		kcuf1		key_right		Cursor right
	79		kH		kll		key_ll		End (Home down)
	80		kd		kcud1		key_down		Cursor down
	81		kN		knp		key_npage		Page down
	82		kI		kich1		key_ic		Insert
	83		kD		kdch1		key_dc		Delete

Characters read from a full-duplex tty are not echoed. 

If the current file is a half-duplex tty (see io(inc)), inkeyS simply allocates and returns a string consisting of a single character read from the current file. 

This function resets the current file. 

SEE ALSO

io(inc), string(inc), alarm(io), initio(io)
inkey$(vrbl)
terminfo(4) or termcap(5) in the UNIX Programmer’s Manual

BUGS

If a character sequence arrives very late in the time allotted, the end of the sequence may be lost and not recognized as a sequence. 

If this function is used to poll the file during other processing and there is no input available, a delay is created. 

from The Basmark QuickBASIC Programmer’s Manual by Lawrence Leinweber