COMMAND INDEX    (TRADUZIONE DISPONIBILE)

!	logical negation of a Boolean value
&	performs a logical bit-wise AND of two bit patterns.
&&	logical AND of a true/false status of two values
&=	a logical bit-wise AND of two bit patterns, whereby the first pattern must be in an integer variable.
'	program comments
*=	multiplies a numeric variable with a numeric expression.
++	increments a numeric variable.
+=	adds a numeric expression to a numeric variable.

--	decrements a numeric variable.
-=	subtracts a numeric expression from a numeric variable.
/*...*/	program comments
//	program comments
/=	divides a numeric expression into a numeric variable.
<<	shifts a bit pattern left.
>>	shifts a bit pattern right.
@	unconditional branch
^=	performs an exclusive bit-wise OR on two bit patterns, whereby the first pattern must be in an 
integer variable.

^^	logical XOR of true/false status of two values
_DATA	positions the data pointer for READ at a value previously determined with the _DATA function.
_DC()	returns the handle of the Device Context for a window area.
_dosCmd$	returns the MS-DOS or MS-Windows command string (from the command line).
_FILE(n)	returns the MS-DOS or MS-Windows file handle of the opened file #n. If file #n is not opened a 0 is 
returned, or in case of devices (CON: LPT1:...) a negative number is returned.

_WDC()	returns the handle of a display area on total screen area.
_X	contains the width of the current window in pixels.
_Y	contains the height of the current window in pixels.
{}	reads a double word (32 bits) from an address.
{}=	writes a double word (32 bits) to an address.
|	performs a logical bit-wise OR on two bit patterns.
|=	performs a logical bit-wise OR on two bit patterns, whereby the first pattern must be in an integer 
variable.

||	logical OR of a true/false status of two values
~	a bitwise NOT
~	voids a numeric expression.
ABS()	returns the absolute value of a numeric expression.
ACOS()	returns the arc cosine of a numeric expression.
ADD	adds a numeric expression to a numeric variable.
ADD()	adds up two or more integer expressions.
ADJUSTW	calculates the measurements of a window based on the given window client area.

ALERT	draws an Alert Box on the screen.
AND	performs a logical bit-wise AND of two bit patterns
AND()	performs a logical bit-wise AND of two bit patterns
ARCOSH()	returns the hyperbolic cosine area of a numeric expression.
ARRANGEICONS	arranges iconized Child windows (minimized Child windows) within a given window in rows.
ARRAYFILL	initiallizes a numerical array of any type with a value.
ARRPTR()	returns the hyperbolic sine area of a numeric expression.

ARTANH()	returns the hyperbolic tangent area of a numeric expression.
ASC()	determines the ASCII value of the first character in a string.
ASIN()	returns the arc sine of a numeric expression.
ATAN()	returns the arc tangent of a numeric expression.
ATN()	returns the arc tangent of a numeric expression.
BCHG()	changes the status of a bit in an integer expression.
BCLR()	clears one bit in an integer expression.

BEEP	sounds a warning.
BGET	fast read of files saved with BPUT.
BIN$()	converts an integer expression to a binary string representation.
BITBLT	copies a source raster (Bitmap) to a destination raster.
BLOAD	fast load of files saved with BSAVE.
BMOVE	copies an area of memory.
BOUND()	bounds test
BOUNDB()	bounds test
BOUNDC()	bounds test
BOUNDW()	bounds test
BOX	draws a rectangle.

BPUT	fast save of an area of memory to disk.
BSAVE	fast save of an area of memory to disk.
BSET()	sets one bit in an integer expression.
BTST()	tests the bit status in an integer expression.
BYTE()	masks with 255
BYTE{}	reads a byte from an address.
BYTE{}=	writes a byte-sized (8 bits) signed integer expression to an address.
C	invokes a subroutine written in C or assembler.
CALL	invokes a subroutine written in C or assembler.

CARD()	performs an AND 65535
CARD{}	reads a word (16 bits) from an address.
CARD{}=	writes a word (16 bits) to an address.
CASE	a part of the SELECT...CASE structure. It contains the condition test.
CEIL()	returns the smallest integer number greater than or equal to a numeric expression.
CFLOAT()	converts an integer into a floating point number.
CHAIN	loads a GFA-BASIC program in memory and runs it.
CHAR{}	reads a string from an address until the next zero byte.

CHAR{}=	writes a string to an address.
CHDIR	sets the current directory.
CHDRIVE	sets the current drive.
CHILDW	creates a Child window within a window.
CHR$()	converts an integer expression into a character.
CINT()	converts a floating point number to an integer.
CIRCLE	draws a circle.
CLEAR	deletes all variables and arrays.
CLEARW#	deletes the contents of a window.
CLIP	sets the bounds for graphic output.

CLIPCOPY	copies data, whose data format was previously set with CLIPFORMAT, to the clipboard.
CLIPCURSOR	limits the movements of the mouse cursor to a rectangle.
CLIPFORMAT	sets a data handle for input/output operations to and from the clipboard.
CLIPPASTE	reads data, with the data format previously set with CLIPFORMAT, from the clipboard.
CLOSE	closes a channel.
CLOSEDIALOG	deletes a dialog box shown with SHOWDIALOG from the screen.

CLOSEMETA	closes previously created metafile.
CLOSEW#	closes a window.
CLR	deletes all variables listed after this command.
CLRCLIP	deletes the contents of the clipboard.
CLS	clears the screen.
COLOR	sets the character COLOR.
COMBIN()	returns the number of combinations of n elements to k-th order without repetition.
CONT	1. a part of the SELECT...CASE structure. It performs an unconditional branch to the next CASE or 
DEFAULT.

COS()	returns the cosine of a numeric expression.
COSH()	returns the hyperbolic cosine of a numeric expression.
COSQ()	returns the extrapolated cosine of a numeric expression.
CREATEBMP()	creates a bitmap.
CREATEMETA	opens/creates a metafile.
CRSCOL	returns the current cursor position.
CRSLIN	returns the current cursor position.
CURVE	draws a Bezier curve.
CVD()	converts the first eight characters in a string from binary to IEEE double format.

CVI()	converts the first two characters in a string to a 16 bit integer.
CVL()	converts the first four characters in a string to a 32 bit integer.
CVS()	converts the first four characters in a string from binary to IEEE single format.
DATA	declares numerical and/or string constants.
DATE$	returns the system date.
DATE$=	sets the system date.
DEC	decrements a numeric variable.
DEC$()	converts an integer expression to decimal representation.

DECL	Declares a function in a DLL
DEFAULT	a part of the SELECT...CASE structure. It contains a branch directive which is performed when 
either none of the CASE conditions is met or a CONT is used to explicitly branch to DEFAULT.
DEFBIT	declares specified variables as Boolean (bit) variables.
DEFBYT	declares specified variables as 1 byte (8 bit) integer variables.
DEFDBL	declares specified variables as 8 byte (64 bit) floating point variables.

DEFFILL	defines a fill pattern.
DEFFLT	declares specified variables as 8 byte (64 bit) floating point variables.
DEFFN	defines one-line functions.
DEFINT	declares specified variables as 4 byte (32 bit) integer variables.
DEFLINE	defines the line type.
DEFMOUSE	sets the mouse.
DEFNUM	sets the formatting of output of numbers with all variations of PRINT.
DEFSNG	declares specified variables as 8 byte (64 bit) floating point variables.

DEFSTR	declares specified variables as string variables.
DEFWRD	declares specified variables as 2 byte (16 bit) integer variables.
DEG()	returns the angle of a numeric expression in degrees.
DELAY	interrupts a program.
DELETE	deletes an element from a one-dimensional array of any variable type.
DFREE()	determines the amount of free disk space on current drive.
DIALOG	creates the header for a Dialog structure.

DIM	creates an array of any variable type
DIM?()	returns the number of elements in a numeric array or the number of strings in a string array.
DIR$()	sets the current path name.
DIR...TO	prints the directories in current path name.
DISABLEW	disables mouse and keyboard input for a window.
DIV	divides a numeric expression into a numeric variable.
DIV()	divides two integer expressions.
DLG()	returns the handle of a dialog structure.

DLGBASE	scales the measurements of dialog boxes and Dialog Controls.
DLGITEM()	returns the handle of a dialog item.
DLL	opens a DLL (dynamic link library).
DO...LOOP	an infinite programming loop, which runs "endlessly" and can only be interrupted by the command 
EXIT IF.
DOUBLE{}	reads a 64-bit IEEE double number from an address.
DOUBLE{}	writes a 64-bit IEEE double number to an address.
DPEEK()	reads two bytes (16 bits) from an address.

DPOKE	writes a word (16 bits) to an address.
DRAGBOX Graphic	moves a graphic segment around the screen.
DRAW	draws a point or a line between two points on the screen.
DRAWTEXT	displays formatted text.
EDIT	returns to the GFA-BASIC editor without deleting the program.
ELLIPSE	draws an ellipse.
 ENABLED?()	returns TRUE if the mouse and keyboard input is currently possible in the window specified in wh&.
ENABLEW	enables mouse and keyboard input for a window.

END	terminates a GFA-BASIC program.
ENDDIALOG	indicates the end of a dialog structure.
ENDDLL	closes a DLL command including the declaration commands.
EOF()	tests if the data pointer points to the end of a file.
EQV()	returns the bit-wise equivalent of two bit patterns.
ERASE	deletes all arrays listed after it.
ERR	invokes an error
ERR$()	determines an error.
ERROR	triggers an error.

EVEN()	tests if a numeric expression is even and returns -1 (true) if it is, or 0 if the expression is odd.
EXEC	loads and runs a program from within the GFA-BASIC interpreter.
EXEC()	returns a value from the invoked program.
EXIST	determines if a particular file exists.
EXIT IF	serves to terminate a loop when the condition following EXIT...IF is logically "true".
EXP()	returns the EULER's number e (= 2.178...) to the power of a numeric expression.

FACT()	returns the factorial of a natural number.
FALSE	0 constant for logical false
FATAL	evaluates an error.
FGETDTA	returns the address of the disk transfer area (DTA).
FIELD # ...AS...AT	random access file management
FILES...TO	prints the directories in the current path name.
FILESELECT	file selection
FILL	fills any enclosed area.
FILLMODE	sets the fill mode.
FIX()	returns the integer portion of a numeric expression.

FLASH	flashes a window by toggling the active/inactive mode.
FLOOR()	returns the next smaller integer number.
FN	unconditional branch.
FOR...NEXT	a programming loop which is executed the specified number of times.
FORM INPUT	entry of string variables
FORM INPUT AS	entry of string variables
FRAC()	returns the fractional part of a numeric expression.
FRE()	reports the amount of free (main) memory.

FREEBMP	deletes from memory a bitmap created with CREATEBMP.
FREEDC	deletes a Device Context (handle).
FREEDLL	releases a DLL (dynamic link library)
FSETDTA	sets new address for the disk transfer area.
FSFIRST()	searches for the first file that satisfies given criteria.
FSNEXT()	searches for the next file according to the criteria set with FSFIRST.
FULLW#	expands a window to its maximum size
FUNCTION...name...ENDFUNC	evaluates an arithmetic expression which is repeatedly used throughout the program, 
whereby the result of the expression changes depending on the variables passed to it.

GET	saves a portion of the screen in a string variable or a bitmap.
GET #	reads a record from a random access file.
GETDEVCAPS()	returns information about a specific output device.
GETEVENT	monitors menu and window events
GETNEAREST();	returns a value for the COLOR command which comes closest to the given RGB value.
GETSIZE()	returns the size of a rectangle in bytes.
GETWINRECT	returns the origin as well as the width and height of a window including its border.

GOSUB	unconditional branch
GOTO	unconditional branch
GRAPHMODE	control of graphic output on bit level
GRAYTEXT	displays given text in gray.
HEX$()	converts an integer expression to hexadecimal representation.
HIBYTE()	returns the high byte in a word expression.
HICARD()	returns the high word in a longword expression. The expression is treated as unsigned.
HIDEM	hides the mouse pointer.
HIWORD()	returns the high word in a longword expression.

HTAB	cursor positioning
ICONIC?()	returns TRUE if the window is iconized.
IF...ENDIF	a conditional branch statement allowing for execution of specific program segments only when a 
condition is logically "true".
IMP()	a logical bit-wise combination of two bit patterns
INC	increments a numeric variable.
INKEY$	reads a character from the keyboard (excluding special keys like Shift, Alt, Alt Gr, Ctrl...). 
INP(#n)	reads a byte from a previously opened file.

INP(PORT)	reads a byte from a port.
INPUT	entry of variables or lists of variables, with or without the prompt
INPUT #	reads data from a previously opened file.
INPUT$	reads a string from the keyboard or a file.
INSERT	inserts a numeric or a string expression at the specified place in a one-dimensional array of 
corresponding variable type.
INSTR()	searches a string expression for occurrence of a substring, optionally from a given position. If the 
substring is found, the position at which it begins is returned. If the substring is not found a 0 is 
returned.

INT()	returns the integer portion of a numeric expression.
INT{}	reads a word (16 bits) from an address.
INT{}=	writes a word (16 bits) to an address.
INVALIDATE	marks a specified rectangle for redraw.
INVERT	displays the contents of a rectangle in inverse.
KEYGET	gets the first character in the keyboard buffer.
KEYTEST	reads the first character in the keyboard buffer.
KILL	deletes a file
KILLEVENT	deletes redraw messages.

KILLTIMER	deletes a timer event.
LCASE$()	converts all capital letters of a string expression to lower case letters, with the exception of PC 
umlauts (US character table).
LEFT$()	returns the first characters of a string expression.
LEN()	determines the length of a character string.
LET	assignment of variables
LINE	draws a line on the screen.
LINE INPUT	entry of string variables or lists of string variables with or without a prompt.

LINE INPUT #	reads strings from a previously opened file.
LIST	displays the current program.
LOAD	loads a GFA-BASIC program into GFA-BASIC editor.
LOADBMP()	loads a bitmap and returns a handle.
LOBYTE()	returns the low byte in a word expression.
LOC()	returns the current position of the file data pointer.
LOCAL	defines local variables in a subroutine.
LOCARD()	returns the low word in a longword expression. The expression is treated as unsigned.

LOCATE	cursor positioning
LOCAXY	places the cursor at column, line.
LOCAYX	places the cursor at line, column.
LOF()	determines the length of a file.
LOG()	returns the natural logarithm of a numeric expression.
LOG10()	returns the base 10 logarithm of a numeric expression.
LOG2()	returns the binary logarithm of a numeric expression.
LONG{}	reads a double word (32 bits) from an address.
LONG{}=	writes a double word (32 bits) to an address.

LOWER$()	converts all capital letters of a string expression including all PC umlauts (IBM character set) to 
lower case letters.
LOWORD()	returns the low word in a longword expression.
LPEEK()	reads a double word (32 bits) from an address.
LPOKE	writes a double word (32 bits) to an address.
LSET	moves a string expression, left justified, to a string.
MAKELONG()	creates a longword integer variable out of two word integer expressions.

MALLOC()	reserves memory.
MAPMODE	sets the conversion mode for the current Device Context.
MAT ADD	adds all elements in two (one- or two-dimensional) floating point arrays.
MAT BASE	sets the row and column offsets for array indexing.
MAT CLR	sets all elements in a one- or two-dimensional floating point array to 0.
MAT CPY	copies a number of rows with a number of elements, from row/column offset in the source matrix to 
row/column offset in the target matrix.

MAT DET	calculates the determinant of a two-dimensional floating point array which is interpreted as a matrix.
MAT INPUT #	reads a file into a floating point array.
MAT INV	calculates an inverse of a two-dimensional floating point array which is interpreted as a matrix.
MAT MUL	multiplies one- or two-dimensional floating point arrays which are interpreted as matrices.
MAT NEG	negates all elements in a one- or two-dimensional floating point array

MAT NORM	row- or column-wise normalising of a two-dimensional floating point array which is interpreted as a 
matrix.
MAT ONE	creates a unitary matrix.
MAT PRINT	prints the elements of an array to screen or a channel.
MAT QDET	calculates the determinant of a two-dimensional floating point array which is interpreted as a matrix.
MAT RANK	returns the rank of a two-dimensional floating point array which is interpreted as a matrix.

MAT READ	reads values from DATA lines into a floating point array.
MAT SET	assigns a value to all elements of a one- or two-dimensional floating point array.
MAT SUB	subtracts all elements in two (one- or two-dimensional) floating point arrays.
MAT TRANS	copies a transposed source matrix into a target matrix.
MAT XCPY	copies a specified number of rows containing a specified number of elements, from the given 
row/column offset in source matrix to the given row/column offset in target matrix. The source 
matrix, or the relevant part of it, are internally transposed before copying.

MAX()	returns the largest argument.
MEMAND	performs a logical bit-wise AND of two bit patterns in memory.
MEMBFILL	fills memory area with a byte value.
MEMDC()	creates a memory Device Context (DC), which is compatible to the given Device Context.
MEMLFILL	fills memory area with a longword (4-byte) value.
MEMOR	performs a logical bit-wise OR of two bit patterns in memory.
MEMWFILL	fills memory area with a word (2-byte) value.

MEMXOR	performs a logical bit-wise XOR of two bit patterns in memory.
MENU	displays a menu bar.
MENU KILL	removes a pop-up menu
MENU()	event management in pop-up menus and windows
MESSAGE	creates a message box.
MFREE()	releases reserved memory.
MID$	moves a string expression of specified length to the chosen place in a character string.
MID$()	starting from position p, returns the next m characters of a string expression.

MIN()	returns the smallest argument.
MIRROR$()	generates a string which is a mirror image of the given character expression.
MKD$()	converts a 64-bit floating point expression to eight characters in IEEE double format.
MKDIR	creates a directory.
MKI$()	converts a 16-bit integer expression to two characters.
MKS$()	converts a 32-bit floating point expression into IEEE single format in four characters.
MOD	calculates the modulo of an integer expression based on the second integer expression.

Monitor	debugger breakpoint.
MOUSE	returns the current X and Y coordinates of the mouse pointer, the status of the mouse buttons and 
(optionally) the status of the keyboard shift keys (KB shift).
MOUSEK	returns the current status of the mouse buttons.
MOUSESX	returns the current x position of the mouse in pixels relative to the upper left corner of the Desktop.
MOUSESY	returns the current y position of the mouse in pixels relative to the upper left corner of the Desktop.

MOUSEX	returns the current X coordinate of the mouse pointer.
MOVEW #	moves a window.
MSHRINK()	decrements reserved memory
MUL	multiplies a numeric variable with a numeric expression.
MUL()	multiplies two or more integer expressions.
NAME...AS	renames a file.
NEW	deletes the current program in main memory.
NOT	performs a logical bit-wise NOT.
OCT$()	converts an integer expression to octal representation.

ODD()	tests if a numeric expression is odd and returns -1 (true) if it is, or 0 if the expression is even.
ON BREAK	turns on the operating system monitoring of Control + Break key combination.
ON BREAK CONT	turns off the Control+Break key combination.
ON BREAK GOSUB	performs a branch when Control+Break key combination is pressed.
ON ERROR	turns on the reporting of error messages by the operating system or GFA-BASIC.
ON ERROR GOSUB	jumps to a routine when an error occurs

ON MENU	monitors events in menus and windows
ON MENU GOSUB	a branch based on a menu event
ON MENU KEY GOSUB	a branch based on a menu event
ON MENU MESSAGE GOSUB	a branch based on a menu event
ON...GOSUB	performs a branch to a subroutine specified after GOSUB, conditional on the value of the 
expression after ON.
OPEN	opens a data channel to a file or a peripheral device.
OPENW#	opens a window.
OPTION BASE	sets the starting offset for row/column indexing of arrays.

OR	performs a logical bit-wise OR on two bit patterns.
OR()	performs a logical bit-wise OR on two bit patterns.
OUT #n	sends a byte to an already opened file.
OUT PORT	hardware access
P	saves a parameter list on stack.
PARENT()	reports the parent window number for the given child window.
PARENTW	creates a window same as OPENW, however, it uses the style flags to configure the window.
PATBLT;	combines the given rectangle with the current fill pattern.

PAUSE	interrupts a program.
PBOX	draws a filled rectangle.
PCIRCLE	draws a filled circle.
PEEK$()	writes the contents of memory to a string variable.
PEEK()	reads a byte (8 bits) from an address.
PEEKEVENT	monitors menu and window events
PELLIPSE	draws a filled ellipse.
PI	contains the constant (3.14...).
PLAYMETA	outputs a metafile into a specified Device Context.
PLOT	draws a point on the screen.

POINT	returns the colour of a point.
POKE	writes a byte (8 bits) to an address.
POKE$	writes to memory from a string variable.
POLYFILL	fills a polygon with a pattern.
POLYLINE	draws connected lines with an arbitrary number of corners.
POPUP()	creates a pop-up menu.
POS()	returns the number of characters printed since the last carriage return.
POSTMESSAGE	posts a message in the message queue of an application program (window). The function does not 
wait (like SENDMESSAGE) for the message to be processed. The posted message is retrieved by 
calling the Windows functions GetMessage() or PeekMessage().

PRBOX	draws a filled rectangle with rounded corners.
PRED()	calculates the first whole number smaller than an integer expression.
PRED()	returns a character whose ASCII value is one less than the first character of a string expression.
PRINT	output of numerical and/or string expressions
PRINT #	outputs data to a file channel
PRINT #n,USING	output of formatted data to a file channel
PRINT AT	output of numerical and/or string expressions

PRINT AT ... USING	formatted output to screen
PRINT ATXY	output of numeric and/or string expressions at a specific position
PRINT ATYX	output of numeric and/or string expressions at a specific position
PRINT USING	formatted output to screen
PROCEDURE...RETURN	gathers together into a subroutine, program segments which are used repeatedly within the 
program.
PSAVE	saves the current GFA-BASIC program with LIST protection.

PSET	sets a graphic point.
PUT	copies a portion of the screen saved with GET to screen memory.
PUT #	writes a record to a random access file.
QSORT	sorts the elements in an array by its size using the Quicksort algorithm.
QUIT	terminates a GFA-BASIC program and returns back to the calling program.
RAD()	returns the radian equivalent of an angle specified in degrees.
RAND()	returns a 16-bit random integer number in the range from 0 to n-1 inclusive.

RANDOM()	returns an integer random number between 0 (inclusive) and x (exclusive).
RANDOMIZE	seeds the random number generators.
RBOX	draws a rectangle with rounded corners.
RC_INTERSECT()	determines the overlapping area between two rectangles.
READ	reads data from DATA lines into variables.
REALIZE	converts entries in the logical (colour) palette of the current window to system palette.
RECALL #	fast load of text files saved with STORE.

RECORD #	specifies the next record to be read with GET # or written with PUT #.
Register	releases the exclusive mouse input which was limited to a specific window with SETCAPTURE.
RELSEEK #	relative positioning of the data pointer
REM	program comment
RENAME...AS	renames a file.
REPEAT...UNTIL	a terminal program loop which runs until the condition at the end of the loop is logically "true".
RESTORE	positions the data pointer for READ

RESTOREDC	restores a previously save status of a Device Contextes (DC).
RESUME	error handling
RGBCOLOR	sets the component colours from the current window palette
RIGHT$()	returns the last m characters of a string expression.
RINSTR()	searches for a substring in a string expression, optionally from a given position. If the substring is 
found, the position at which the substring begins within the string expression is returned. If the 
substring is not found a 0 is returned.

RMDIR	deletes a directory.
RND	generates a random number between 0 (inclusive) and 1 (exclusive).
ROL()	rotates a bit pattern left.
ROR()	rotates a bit pattern right.
ROUND()	rounds off the numeric expression x.
RSET	moves a string expression, right justified, to a string.
RUBBERBOX	cuts out a rectangular segment of the screen.
RUN	runs the program in memory.
SAVE	saves the current GFA-BASIC program.

SAVEDC	saves information about the status of the current Device Context (DC).
SCALE()	divides an integer variable into the product of two other integer variables.
SEEK #	absolute positioning of the data pointer
SELECT...CASE	A conditional command which enables execution of specified program segments depending on an 
integer expression.
SENDMESSAGE	sends a message to one or more windows. The SENDMESSAGE command does not return before 
the message has been processed. After receiving a SENDMESSAGE call Windows immediately 
calls the relevant window function.

SETCAPTURE	redirects all mouse actions to a specific window.
SETDC	sets a Device Context.
SETMAPPERFLAG	sets the mode for the conversion of a logical font into physical font.
SETMOUSE	sets the mouse cursor to a defined position.
SETTIME	sets the system time and date.
SETTIMER	sets a timer event.
SETWINDOWSTYLE	changes the appearance of a window after OPENW by modifying its attributes.
SGN()	returns the sign of a numeric expression.

SHELL	invokes the command interpreter
SHL()	shifts a bit pattern left.
SHORT()	sign extension
SHORT{}	reads a word (16 bits) from an address.
SHORT{}=	writes a word (16 bits) to an address.
SHOWDIALOG	displays a dialog structure on the screen.
SHOWM	shows the mouse pointer.
SHOWW	displays a window with a certain status.
SHR()	shifts a bit patter right.
SIN()	returns the sine of a numeric expression.

SINGLE{}	reads a 32-bit number in IEEE double format from an address.
SINGLE{}	writes a 32-bit number in IEEE double format to an address.
SINH()	returns the hyperbolic sine of a numeric expression.
SINQ()	returns the extrapolated sine of a numeric expression.
SIZEW #	changes the size of a window.
SLEEP	SLEEP waits for occurrence of a message and branches then to the procedures specified in ON 
MENU xxx GOSUB.
SOUND	sounds a tone of adjustable height and duration.

SPACE$()	creates a string consisting of a specified number of spaces.
SPC	prints spaces.
SQR()	returns the positive square root of a numeric expression.
SSORT	sorts the elements in an array by its size using the Shell-Metzner algorithm.
STACKSIZE	changes the size of GFA-BASIC stack memory.
STOP	halts a GFA-BASIC program.
STORE #	fast save of a string array as a text file
STR$()	converts a numeric expression into a string.

STRETCH	extends or shrinks the dimensions of a bitmap.
STRING$()	creates a string consisting of a string expression repeated specified number of times.
SUB	subtracts a numeric expression from a  numeric variable.
SUB()	subtracts two integer expressions.
SUCC()	calculates the first natural number greater than an integer expression.
SUCC()	returns a character whose ASCII value is one greater than the first character of a string expression.

SWAP	swaps two variables of the same type.
SWAP()	swaps the low and high words.
SWITCH	a part of the SELECT...CASE structure. It contains the condition test.
SYSCOL	sets colours for the menu bar, pull-down menus, pop-up menus and window frames.
SYSCOL()	returns the system colour of a specific element.
SYSMETRIC()	returns the dimensions of a specified element.
SYSTEM	terminates a GFA-BASIC program and returns back to the calling program.

TAB()	prints spaces.
TAN()	returns the tangent of a numeric expression.
TANH()	returns the hyperbolic tangent of a numeric expression.
TEXT	output of an expression as graphic text
TIME$	returns the system time.
TIME$=	sets the system time.
TIMER	returns the time in milliseconds.
TITLEW#	writes a string on the title line of a window.
TOPW#	activates a window.
TOUCH	updates the time and date stamps of a file with current values.

TRACE$	locates errors in a program.
TRIM$	removes spaces at the beginning or end of a string expression.
TROFF	turns off TRON.
TRON	lists commands during program execution.
TRUE	-1 constant
TRUNC()	returns the integer part of a numeric expression.
TYPE	DEFINITION of a file structure
UCASE$()	converts all lower case letters of a string expression to capital letters, with the exception of PC 
umlauts (US character table).

UPDATECOLORS	preforms a conversion of current colours within the given window to system palette on a pixel by 
pixel basis.
UPPER$()	converts all lower case letters of a string expression including all PC umlauts (IBM character set) 
to capital letters.
USHORT()	performs AND 65535.
USHORT{}	reads a word (16 bits) from an address.
USHORT{}=	writes a word (16 bits) to an address.
UWORD()	performs AND 65535
UWORD{}	reads a word (16 bits) from an address.

UWORD{}=	writes a word (16 bits) to an address.
V:	returns the address of a variable or an array element.
VAL()	converts a string expression into a number.
VAL?()	determines how many places of a string expression will be converted when using VAL().
VALIDATE	closes a rectangle during redraw.
VAR	declaration part of the parameter list for a PROCEDURE or FUNCTION, which is followed Call by 
Reference Variables.
VARIAT()	returns the number of permutations of n elements to k-th order without repetition.

VARPTR()	returns the address of a variable or an array element.
VIEWPORT	scales the given Device Context.
VISIBLE?()	returns TRUE if the window (=Top Window) is visible.
VOID	voids a numeric expression.
VTAB	cursor positioning
WHILE...WEND	A terminal program loop which runs until the condition at the beginning of the loop is logically "true".
WIN	selects a window.
WIN();	returns the number of the window where the current output takes place.

WINDGET	reads window parameters.
WINDSET	writes window parameters.
WORD()	sign extension
WORD{}	reads a word (16 bits) from an address.
WORD{}=	writes a word (16 bits) to an address.
WRITE	saves data to sequential files for later read with INPUT #.
XLATE$()	replaces all characters of a string expression with values from a table.
XOR()	performs an exclusive bit-wise OR on two bit patterns.
ZOOMED?()	returns TRUE if the window is maximized.