GWBASIC User's Manual

GW-BASIC User's Guide
slash (/).
/f:n sets the maximum number of files that may be opened simultaneously during the
execution of a GW-BASIC program. Each file requires 194 bytes for the File Control Block
(FCB) plus 128 bytes for the data buffer. The data buffer size may be altered with the /s: switch.
If the /f: switch is omitted, the maximum number of open files defaults to 3. This switch is
ignored unless the /i switch is also specified on the command line.
/i makes GW-BASIC statically allocate space required for file operations, based on the /s and /
f switches.
/s:n sets the maximum record length allowed for use with files. The record length option in the
OPEN statement cannot exceed this value. If the /s: switch is omitted, the record length defaults
to 128 bytes. The maximum record size is 32767.
/c:n controls RS-232 communications. If RS-232 cards are present, /c:0 disables RS-232
support, and any subsequent I/O attempts for each RS-232 card present. If the /c: switch is
omitted, 256 bytes are allocated for the receive buffer and 128 bytes for the transmit buffer for
each card present.
The /c: switch has no affect when RS-232 cards are not present. The /c:n switch allocates n
bytes for the receive buffer and 128 bytes for the transmit buffer for each RS-232 card present.
/m:n[,n] sets the highest memory location (first n) and maximum block size (second n) used
by GW-BASIC. GW-BASIC attempts to allocate 64K bytes of memory for the data and stack
segments. If machine language subroutines are to be used with GW-BASIC programs, use the /
m: switch to set the highest location that GW-BASIC can use. The maximum block size is in
multiples of 16. It is used to reserve space for user programs (assembly language subroutines)
beyond GW-BASIC's workspace.
The default for maximum block size is the highest memory location. The default for the highest
memory location is 64K bytes unless maximum block size is specified, in which case the default
is the maximum block size (in multiples of 16).
/d allows certain functions to return double-precision results. When the /d switch is specified,
approximately 3000 bytes of additional code space are used. The functions affected are ATN, COS,
EXP, LOG, SIN, SQR, and TAN.
Note
All switch numbers may be specified as decimal, octal (preceded by &O), or hexadecimal
(preceded by &H).
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