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smallfun.txt
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1991-01-26
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SMALLEXE: Functions and Subprograms
T. G. Muench January 1991
FileExist FUNCTION
Description: Checks to see if a file exists so that
it may be opened by BASIC
Usage: EXIST = FileExist(FILE$)
Replaces: No direct BASIC equivalent; use in place
of BASIC's ON ERROR
Parameters:
Input FILE$ File specification
Output EXIST TRUE / FALSE
Remarks: Uses DOS function to open the specified
file without causing a BASIC error
GetInput SUBROUTINE
Description: Gets user input from keyboard
Usage: CALL GetInput(PROMPT$, ENTRY$)
Replaces: INPUT "PROMPT$"; ENTRY$
Parameters:
Input PROMPT$ Optional prompt to display
Output ENTRY$ String entered by user
Remarks: Very limited line editing - supports
only BackSpace to correct backwards;
there is also no check for off-screen
InputLine SUBROUTINE
Description: Input a line of text from a file
Usage: CALL InputLine (IOCHAN, BUFSIZE, _
STATUS, TEXT$)
Replaces: LINE INPUT #IOCHAN, TEXT$
Parameters:
Input IOCHAN I/O channel number
BUFSIZE Size of I/O buffer to use
STATUS Flags first access of file
Output STATUS Flags end of file
TEXT$ Line of text from file
Remarks: Much faster than LINE INPUT #; make the
buffersize as large as possible to min-
imize accesses to the disk
ReadData$ FUNCTION
Description: Returns the next string element from the
passed data string
Usage: STRVAR$ = ReadData$(DATA$)
Replaces: READ STRVAR$
Parameters:
Input DATA$ Data string to parse
Output STRVAR$ Next element in DATA$
Remarks: DATA$ must contain string elements sep-
arated by commas with no spaces, i.e.
"ONE,TWO,THREE"
ReadTimer& FUNCTION
Description: Returns the number of ticks elapsed
since midnight
Usage: TICKS& = ReadTimer&
Replaces: START! = TIMER
Parameters:
Input None
Output TICKS& Longword timer count
Remarks: The clock ticks approximately 18.2 times
per second; there is no checking for
passing midnight when the clock is reset
StrToInt& FUNCTION
Description: Returns the long integer equivalent of
a numeric string
Usage: NUMBER& = StrToInt&(NUMSTR$)
Replaces: NUMBER& = VAL(NUMSTR$)
Parameters:
Input NUMSTR$ Numeric string to convert
Output NUMBER& Long integer equivalent
Remarks: Stops when a non-numeric character is
encountered; no check for overflow