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Frequently asked questions about QB64

Arrays and Data Storage

Arrays

_DEFINE (statement) defines a range of untyped variable names according to their first character as a datatype.
_PRESERVE (REDIM option) preserves the existing element values when an array is resized.
CLEAR (statement) resets all variable values and array element values to 0 or null strings and closes all open files.
DIM (statement) dimensions(sizes) a static array and defines the type.
$DYNAMIC (metacommand) defines that all arrays are dynamic or changeable in size.
ERASE (array statement) clears a static array of all values and totally removes a dynamic array.
LBOUND (function) returns the lowest valid index (lower boundary) of an array.
OPTION BASE (statement) sets the default starting index of an array to 0 or 1.
REDIM (statement) re-dimensions the number of elements in a dynamic(resizeable) array and defines the type.
SHARED (statement) designates variable values that can be shared with sub-procedures without using parameters.
STATIC (statement) defines a variable or list of variables that will retain their values after the sub-procedure is exited.
$STATIC (metacommand) defines that all arrays are static or unchangeable in size.
SWAP (statement) trades the values of two numerical or string values or array elements.
UBOUND (function) returns the highest valid index (upper boundary) of an array.

Colors and Transparency

_ALPHA (function) returns the alpha channel transparency level of a color value used on a screen page or image.
_ALPHA32 (function) function returns the alpha channel level of a 32 bit color value only.
_BACKGROUNDCOLOR (function) returns the current background color for an image handle or page.
_BLEND (statement) turns on alpha blending for the current image or a specific one.
_BLEND (function) returns if blending is enabled or disabled for the current window or a specified image handle.
_BLINK (statement) statement turns blinking colors on/off in SCREEN 0
_BLINK (function) returns -1 if enabled or 0 if disabled by _BLINK statement.
_BLUE (function) returns the palette intensity OR the blue component intensity of a 32-bit image color.
_BLUE32 (function) returns the blue component intensity of a 32-bit image color.
_BRIGHTNESS32 (function) returns the brightness value (HSB colorspace) of a given 32-bit ARGB color.
_CLEARCOLOR (statement) sets a specific color to be treated as transparent in an image
_CLEARCOLOR (function) returns the current transparent color of an image.
_COLORCHOOSERDIALOG (function) Displays a standard color picker dialog box and returns a 32-bit RGBA color selected by the user.
_COPYPALETTE (statement) copies the color palette intensities from one image to another image or screen page.
_DEFAULTCOLOR (function) returns the current default (text/drawing) color for an image handle or page.
_DONTBLEND (statement) turns off alpha blending for an image handle.
_GREEN (function) returns the palette index OR the green component intensity of a 32-bit image.
_GREEN32 (function) returns the green component intensity of a 32-bit image color.
_HSB32 (function) returns the 32-bit ARGB color value equivalent to the specified HSB colorspace values.
_HSBA32 (function) returns the 32-bit ARGB color value equivalent to the specified HSB colorspace values + alpha channel.
_HUE32 (function) returns the hue value (HSB colorspace) of a given 32-bit ARGB color.
_NEWIMAGE (function) prepares a custom sized program SCREEN or page surface that can use 256 or 32 bit colors.
_PALETTECOLOR (statement) sets the color value of a palette entry of an image using 256 color modes or less (4 or 8 BPP).
_PALETTECOLOR (function) returns the 32 bit attribute color setting of an image or screen page handle's palette.
_PIXELSIZE (function) returns the color depth (Bits Per Pixel) of an image.
_RED (function) returns the palette index OR the red component intensity of a 32-bit screen.
_RED32 (function) returns the red component intensity of a 32-bit image color.
_RGB (function) returns the closest palette attribute index OR the LONG 32 bit color value in 32 bit screens.
_RGB32 (function) returns the LONG 32 bit color value only.
_RGBA (function) returns the closest palette attribute index OR the LONG 32 bit color value in _ALPHA screens.
_RGBA32 (function) returns the LONG 32 bit _ALPHA color value only.
_SATURATION32 (function) returns the saturation value (HSB colorspace) of a given 32-bit ARGB color.
_SETALPHA (statement) sets the alpha channel transparency level of some or all of the pixel colors of an image.

CLS (statement) clears the screen and can set the background color in QB64.
COLOR (statement) sets the current text color attribute or _RGB value to be used or background colors in some screen modes.
INP (function) returns the RGB color intensity values from color port register &H3C9 for a specific attributes.
OUT (statement) sets the color port access mode and sets the RGB color intensity values using &H3C9.
PALETTE (statement) sets the Red, Green and Blue color attribute intensities using a RGB multiplier calculation.
PALETTE USING (statement) sets the color intensity settings using a designated array.
POINT (function) returns a pixel coordinate color attribute or the LONG _RGB color value of a 32 bit color.
PRESET (statement) sets a pixel coordinate to the background color or a color specified.
PSET (statement) sets a pixel coordinate a specified color or uses the current color when not designated.
SCREEN sets the screen mode of a program which may determine the number of colors available in legacy modes.

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Console Window

$CONSOLE (metacommand) creates a console window that can be used throughout a program.
_CONSOLE (statement) used to turn a console window OFF or ON or to designate _DEST _CONSOLE for output.
_CONSOLEINPUT (function) fetches input data from a $CONSOLE window to be read later (both mouse and keyboard)
_CINP (function) Returns a key code from $CONSOLE input
_CONSOLECURSOR (statement) is used to switch the text cursor in Console Windows off/on or change its size.
_CONSOLEFONT (statement) is used to change the text font used in Console Windows or change its size.
_CONSOLETITLE (statement) creates the title of the console window using a literal or variable string.
$SCREENHIDE (metacommand) hides the program window throughout the program until $SCREENSHOW is used.
_SCREENHIDE hides the main program window in a section of code until _SCREENSHOW is used.
$SCREENSHOW (metacommand) displays the main program window throughout the program after $SCREENHIDE has been used.
_SCREENSHOW displays the main program window in a section of code after _SCREENHIDE has been used.
SHELL (function) executes a DOS command or calls another program. Returns codes sent by END or SYSTEM.
_SHELLHIDE (function) hides a DOS command or call to another program. Returns codes sent by END or SYSTEM.

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Conditional Operations

AND (boolean) returns True if all of the arguments are True.
_ANDALSO (boolean) performs short-circuiting logical conjunction on two expressions.
_IIF (function) provides conditional evaluations similar to a ternary operator, with short-circuiting behavior.
_NEGATE (boolean) returns True when a boolean evaluation is False and vice-versa.
NOT (boolean) returns the opposite condition of an argument.
OR (boolean) returns True if one of the arguments is True.
_ORELSE (boolean) performs short-circuiting inclusive logical disjunction on two expressions.
XOR (boolean) returns True if only one of two arguments are True.

See also: Logical Operations and Relational Operations

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Definitions and Variable Types

_BIT {` numerical type) values of 0 (bit off) or -1 (bit on). Unsigned of 0 or 1.
_BYTE {%% numerical type) values from -128 to 127 (one byte or 8 _BITs). Unsigned from 0 to 255.
_DEFINE (statement) defines a range of untyped variable names according to their first character as a datatype.
_FLOAT {## numerical type) values offer the maximum floating-point decimal precision available using QB64.
_INTEGER64 (&& numerical type) values -9223372036854775808 to 9223372036854775807. Unsigned to 18446744073709551615.
_MEM (variable type) contains read only dot elements for the OFFSET, SIZE, TYPE and ELEMENTSIZE of a block of memory.
_OFFSET(%& variable type) can store any memory offset integer value when using DECLARE LIBRARY or _MEMory only.
_UNSIGNED {~ numerical type) defines an integer numerical value as being positive only in QB64.
COMMON (statement) shares common variable values with other Linked or CHAINed programs.
COMMON SHARED (statement) shares common variable values with all sub-procedures and other Linked or CHAINed programs.
CONST (statement) defines one or more named numeric or string shared values which can not change in a program.
DEFDBL (statement) defines undefined variable starting letters AS DOUBLE variables instead of the SINGLE type default.
DEFINT (statement) defines undefined variable starting letters AS INTEGER variables instead of the SINGLE type default.
DEFLNG (statement) defines undefined variable starting letters AS LONG variables instead of the SINGLE type default.}}
DEFSNG (statement) defines undefined variable starting letters AS SINGLE variables instead of the SINGLE type default.
DEFSTR (statement) defines undefined variable starting letters AS STRING variables instead of the SINGLE type default.
DIM defines a variable or size a static array and can define the type of value it returns.
DOUBLE {# numerical type) an 8 byte floating decimal variable type with numerical values up to 15 decimal places.
INTEGER {% numerical type) a two byte variable type with values from -32768 to 32767. Unsigned to 65535.
LONG {& numerical type) Integer values can be from -2147483648 to 2147483647. _UNSIGNED values to 4294967295.
OPTION BASE (statement) sets the default starting index of an array to 0 or 1.
REDIM defines and sizes a dynamic(changeable) array and can define the type of value returned.
SHARED (statement) designates variable values that can be shared with sub-procedures without using SUB parameters.
SINGLE (! numerical type) a 4 byte floating decimal variable type with numerical values up to 7 decimal places.
STATIC (statement) defines a variable or list of variables that will retain their values after the sub-procedure is exited.
STRING ($ variable type) one byte text variable with ASCII code values from 0 to 255.
TYPE (statement) defines variable types that can hold more than one variable type value of a fixed byte length.

See also: QB64 Variable Types and C++ Variable Types

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External Disk and API calls

_ACCEPTFILEDROP (statement) turns a program window into a valid drop destination for dragging files from Windows Explorer.
_DEVICE$ (function) returns a STRING expression listing device names and input types of system input devices.
_DEVICES (function) returns the number of input devices found on a computer system.
_DIREXISTS (function) returns -1 if the directory folder name string parameter exists. Zero if it does not.
_DROPPEDFILE (function) returns the list of items (files or folders) dropped in a program's window after _ACCEPTFILEDROP is enabled.
_CLIPBOARD$ (statement) sends STRING data to the Clipboard.
_CLIPBOARD$ (function) returns the current contents of the Clipboard as a string.
_CLIPBOARDIMAGE (function) pastes an image from the clipboard into a new QB64 image in memory.
_CLIPBOARDIMAGE (statement) copies a valid QB64 image to the clipboard.
_CWD$ (function) returns the current working directory path as a STRING.
_DONTWAIT (SHELL action) allows the program to continue without waiting for the other program to close.
_FILEEXISTS (function) returns -1 if the file name string parameter exists. Zero if it does not.
_FINISHDROP (statement) resets _TOTALDROPPEDFILES and clears the _DROPPEDFILE list of items (files/folders).
_HIDE (SHELL action) hides the DOS screen output during a shell.
_LASTBUTTON (function) returns the number of buttons available on a specified number device listed by DEVICE$.
_OPENFILEDIALOG$ (function) Displays a standard dialog box that prompts the user to open a file.
_OS$ (function) returns the QB64 compiler version in which the program was compiled as [WINDOWS], [LINUX] or [MACOSX] and [32BIT] or [64BIT].
_SAVEFILEDIALOG$ (function) Displays a standard dialog box that prompts the user to save a file.
_SCREENCLICK simulates clicking the mouse at a position on the screen to get focus.
_SCREENIMAGE captures the current desktop screen image.
_SCREENPRINT simulates keyboard entries on the desktop.
_SELECTFOLDERDIALOG$ (function) Displays a dialog box that enables the user to select a folder (directory).
_SHELLHIDE (function) executes a DOS command or calls another program. Returns codes sent by END or SYSTEM.
_STARTDIR$ (function) returns the user's program calling path as a STRING.
_TOTALDROPPEDFILES (function) returns the number of items (files or folders) dropped in a program's window after _ACCEPTFILEDROP is enabled.

CHDIR (statement) changes the program path to a new path.
COMMAND$ (function) returns command line parameters sent when a program is started.
ENVIRON (statement) temporarily sets an environmental key/pair value.
ENVIRON$ (function) returns the environmental settings of the computer.
_ENVIRONCOUNT (function) returns the number of key/value pairs currently exist in the environment table.
_FILES$ (function) returns a file or directory name that matches the specified pattern.
FILES (statement) displays a specified list of files.
_FULLPATH$ (function) returns an absolute or full path name for the specified relative path name.
MKDIR (statement) creates a new directory folder in the designated path.
NAME (statement) renames a file.
RMDIR (statement) removes an empty directory folder from the specified path.
SHELL (statement) performs a command line operation in DOS.
SHELL (function) executes a DOS command or calls another program. Returns codes sent by END or SYSTEM.

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Error Trapping, Logging & Debugging

$ASSERTS (metacommand) Enables the _ASSERT macro
$CHECKING (metacommand) turns off or on error event checking and strips error code from compiled programs.
$DEBUG (metacommand) enables debugging features, allowing you to step through your code line by line.

_ASSERT (statement) Performs debug tests.
_ERRORLINE (function) returns the actual text code line where a program error occurred.
_LOGERROR (statement) writes a log message at the Error level with an accompanying stacktrace.
_LOGINFO (statement) writes a log message at the Information level.
_LOGMINLEVEL (function) returns the current minimum logging level that is being output.
_LOGTRACE (statement) writes a log message at the Trace level.
_LOGWARN (statement) writes a log message at the Warning level.

ERR (function) returns the error code number of the last error to occur.
ERROR (statement) simulates a program error based on the error code number used.
ERL (function) returns the closest line number before an error occurred if the program uses them.
ON ERROR (statement) GOTO sends the program to a line number or label when an error occurs. Use to avoid program errors.
RESUME (statement) error statement sends the program to the NEXT code line or a designated line number or label .

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Event Trapping

_AUTODISPLAY (statement) enables the automatic display of the screen image changes previously disabled by _DISPLAY.
_DELAY (statement) suspends program execution for a SINGLE value of seconds down to milliseconds.
_DISPLAY (statement) turns off automatic display while only displaying the screen changes when called.
_EXIT (function) prevents a user exit and indicates if a user has clicked the close X window button or CTRL + BREAK.
_FREETIMER (function) returns a free TIMER number for multiple ON TIMER(n) events.
_MOUSEINPUT (function) reports any changes to the mouse status and MUST be used to read those changes.
_SHELLHIDE (function) returns the code sent by a program exit using END or SYSTEM followed by an INTEGER value.

OFF turns event checking off and does not remember subsequent events.
ON turns event checking on.
ON ERROR GOTO (event statement) executes when a program error occurs
ON KEY(n) (event statement) executes when a keypress or keypress combination occurs.
ON TIMER(n) (event statement) executes when a timed event occurs. QB64 can use multiple numbered timers.
ON...GOSUB (event statement) branches to a line number or label according to a numerical ordered list of labels.
ON...GOTO (event statement) branches to a line number or label according to a numerical ordered list of labels.
STOP suspends event checking and remembers subsequent events that are executed when events are turned back on.
TIMER (function) returns the number of seconds past the previous midnite down to a QB64 accuracy of one millisecond.
TIMER (statement) enables, turns off or stops timer event trapping. In QB64 TIMER(n) FREE can free multiple timers.
WAIT (statement) normally used to delay program display execution during or after vertical retrace periods.

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File Input and Output

_DIREXISTS (function) returns -1 if the directory folder name string parameter exists. Zero if it does not.
_FILEEXISTS (function) returns -1 if the file name string parameter exists. Zero if it does not.
_READFILE$ (function) directly read a file into a string, without OPEN/CLOSE overhead.
_WRITEFILE (statement) directly write a string into a file, without OPEN/CLOSE overhead.
ACCESS (clause) used in a networking OPEN statement to allow READ or WRITE access to files.
APPEND (file mode) opens or creates a file that can be appended with data at the end.
BINARY (file mode) opens or creates a file that can be byte accessed using both GET and PUT.
BLOAD (statement) opens a binary file and loads the contents to a specific array.
BSAVE (statement) creates a binary file that holds the contents of a specified array.
CHDIR (statement) changes the program path to a new path.
CLOSE (statement) closes a specified file or all open files.
EOF (function) returns -1 when the end of a file has been read.
FIELD (statement) creates a STRING type definition for a random-access file buffer.
FILES (statement) displays a specified list of files.
FREEFILE (function) returns a file access number that is currently not in use.
GET (file I/O statement) reads file data by byte or record positions.
INPUT (file mode) only OPENs existing sequential files for program INPUT.
INPUT (file statement) reads sequential file data that was created using PRINT # or WRITE #.
INPUT$ (function) reads a specific number of bytes from random or binary files.
KILL (statement) deletes a specified file without asking for verification. Remove empty folders with RMDIR.
LINE INPUT (file statement) reads an entire text row of printed sequential file data.
LOC (function) finds the current file location or size of a COM port receive buffer.
LOCK (statement) prevents access to a file.
LOF (function) returns the size of a file in bytes.
MKDIR (statement) creates a new folder in the designated path.
NAME (statement) renames a file AS a new file name.
OPEN (file I/O statement) opens a specified file FOR an access mode with a set reference number.
OUTPUT (file mode) opens or creates a new file that holds no data.
PRINT (file statement) writes text and numerical data into a file.
PRINT USING (file statement) writes template formatted text into a file.
PUT (file I/O statement) writes data into a RANDOM or BINARY file by byte or record position.
RANDOM (file mode) opens or creates a file that can be accessed using both GET and PUT.
RESET (statement) closes all files and writes the directory information to a diskette.
RMDIR (statement) removes an empty folder from the specified path.
SEEK (function) returns the current read or write byte position in a file.
SEEK (statement) sets the current read or write byte position in a file.
UNLOCK (statement) unlocks access to a file.
WIDTH (statement) sets the text width of a file.
WRITE (file statement) writes numerical and string data to a sequential file using comma separators.

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Checksums and Hashes

_ADLER32 (function) Returns the Adler-32 checksum of any arbitrary string.
_CRC32 (function) Returns the Crc-32 checksum of any arbitrary string.
_MD5$ (function) Returns the MD5 hash value of any arbitrary string.

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Fonts

_FONT (function) creates a new alphablended font handle from a designated image handle
_FONT (statement) sets the current _LOADFONT function font handle to be used by PRINT or _PRINTSTRING.
_FONTHEIGHT (function) returns the font height of a font handle created by _LOADFONT.
_FONTWIDTH (function) returns the font width of a MONOSPACE font handle created by _LOADFONT.
_FREEFONT (statement) frees a font handle value from memory
_LOADFONT (function) loads a TrueType font (.TTF) file of a specific size and style and returns a font handle value.
_MAPUNICODE (statement) maps a Unicode value to an ASCII character code value.
_PRINTMODE (function) returns the present _PRINTMODE status as a numerical value.
_PRINTMODE (statement) sets the text or _FONT printing mode on a background image when using PRINT or _PRINTSTRING.

_KEEPBACKGROUND (1): Text background transparent. Only the text is displayed over anything behind it.
_ONLYBACKGROUND (2): Text background is only displayed. Text is transparent to anything behind it.
_FILLBACKGROUND (3): Text and background block anything behind them like a normal PRINT. Default setting.

_PRINTSTRING (statement) prints text or custom font strings using graphic column and row coordinate positions.
_PRINTWIDTH (function) returns the width in pixels of the _FONT or text string that a program will print.
PRINT (statement) prints numeric or string expressions to the program screen.
PRINT USING (statement) prints template formatted numeric or string values to the program screen.
_UCHARPOS (function) calculates the starting pixel positions of every character of a (unicode) text string.
_UFONTHEIGHT (function) returns the global glyph height (incl. ascender/descender) of a loaded font.
_ULINESPACING (function) returns the vertical line spacing (distance between two consecutive baselines) in pixels.
_UPRINTSTRING (statement) locates and prints a (unicode) text string using graphic coordinates.
_UPRINTWIDTH (function) returns the pixel width of a (unicode) text string to be printed using _UPRINTSTRING.
WRITE (screen I/O statement) writes a comma-separated list of values to the screen.

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Game Controller Input (Joystick)

_AXIS (function) returns a SINGLE value between -1 and 1 indicating the maximum distance from device axis center 0.
_BUTTON (function) returns -1 when a device button is pressed and 0 when button is released.
_BUTTONCHANGE (function) returns -1 when a device button has been pressed and 1 when released. Zero indicates no change.
_DEVICE$ (function) returns a STRING expression listing a designated numbered input device name and types of input.
_DEVICEINPUT (function) returns the _DEVICES number of an _AXIS, _BUTTON or _WHEEL event.
_DEVICES (function) returns the number of input devices found on a computer system including the keyboard and mouse.
_LASTAXIS (function) returns the number of axis available on a specified number device listed by _DEVICE$.
_LASTBUTTON (function) returns the number of buttons available on a specified number device listed by DEVICE$.
_LASTWHEEL (function) returns the number of scroll wheels available on a specified number device listed by _DEVICE$.
_MOUSEMOVEMENTX (function) returns the relative horizontal position of the mouse cursor compared to the previous position.
_MOUSEMOVEMENTY (function) returns the relative vertical position of the mouse cursor compared to the previous position.
_WHEEL (function) returns -1 when a device wheel is scrolled up and 1 when scrolled down. Zero indicates no activity.
ON STRIG(n) (event statement) directs program flow upon a button press event of a game controller device.
STICK (function) returns the directional axis coordinate values from 1 to 254 of game port (&H201) or USB controller devices.
STRIG (function) returns the True or False button press status of game port (&H201) or USB controller devices.
STRIG(n) (statement) enables, suspends or disables event trapping of STRIG button return values.

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Graphic Commands

_COPYIMAGE (function) can copy a software surface to a hardware accelerated surface handle using mode 33.
_DISPLAY (statement) renders surfaces visible in the _DISPLAYORDER previously set in the QB64 program.
_DISPLAYORDER sets the rendering order of _SOFTWARE, _HARDWARE and _GLRENDER with _DISPLAY.
_LOADIMAGE (function) can load images as hardware accelerated using mode 33.
_PUTIMAGE (statement) can place GL surfaces and allows the _SMOOTH action to blend stretched surfaces.

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Graphics and Imaging:

_AUTODISPLAY (statement) enables the automatic display of the screen image changes previously disabled by _DISPLAY.
_CLIP (PUT action) allows placement of an image partially off of the screen.
_COPYIMAGE (function) function duplicates an image handle from a designated handle.
_COPYPALETTE (statement) copies the color palette intensities from one image to another image or screen page.
_DESKTOPHEIGHT (function) returns the height of the desktop (not program window).
_DESKTOPWIDTH (function) returns the width of the desktop (not program window).
_DEST (statement) sets the current write image or page. All graphics will go to this image.
_DEST (function) returns the current write destination image or page.
_DISPLAY (statement) turns off automatic display while only displaying the screen changes when called.
_DISPLAY (function) returns the handle of the current image that is displayed on the screen.
_FULLSCREEN (function) returns the present full screen mode setting of the screen window.
_FULLSCREEN (statement) sets the full screen mode of the screen window. Alt + Enter can do it manually.
_FREEIMAGE (statement) releases an image handle value from memory when no longer needed.
_HEIGHT (function) returns the height of an image handle or current write page.
_ICON (function) places an image in the title bar using a _LOADIMAGE handle.
_LOADIMAGE (function) loads a graphic file image into memory and returns an image handle.
_MAPTRIANGLE (statement) maps a triangular portion of an image to a destination image or screen page.
_NEWIMAGE (function) prepares a window image or page surface and returns the handle value.
_PIXELSIZE (function) returns the color depth (Bits Per Pixel) of an image.
_PRINTSTRING (statement) prints text or custom font strings using graphic column and row coordinate positions.
_PUTIMAGE (statement) maps a rectangular area of a source image to an area of a destination image in one operation
_SAVEIMAGE (statement) Saves the screen or an image handle to an image file.
_SCREENIMAGE (function) creates an image of the current desktop and returns an image handle.
_SMOOTH (function) checks whether the current _FULLSCREEN mode has antialiasing enabled or not.
_SOURCE (statement) establishes the image SOURCE using a designated image handle
_SOURCE (function) returns the present image _SOURCE handle value.
_UCHARPOS (function) calculates the starting pixel positions of every character of a (unicode) text string.
_UPRINTSTRING (statement) locates and prints a (unicode) text string using graphic coordinates.
_WIDTH (function) returns the width of an image handle or current write page.

CIRCLE (statement) is used in graphics SCREEN modes to create circles, arcs or ellipses.
CLS (statement) clears a screen page or the program SCREEN. QB64 can clear with a color.
COLOR (statement) sets the current text color attribute or _RGB value to be used or background colors in some screen modes.
DRAW (statement) uses a special type of string expression to draw lines on the screen.
GET (graphics statement) used to store a box area image of the screen into an INTEGER array.
LINE (statement) used in graphic SCREEN modes to create lines or boxes.
PAINT (statement) used to color enclosed graphic objects with a designated fill color and border color.
PALETTE (statement) can swap color settings, set colors to default or set the Red, Green, Blue color palette.
PALETTE USING (statement) sets all RGB screen color intensities using values from an array.
PCOPY (statement) copies one source screen page to a destination page in memory.
PMAP (function) returns the physical or WINDOW view coordinates.
POINT (function) returns the pixel COLOR attribute or _RGB value at a specified graphics coordinate.
PRESET (statement) sets a pixel coordinate to the background color or a designated color.
PSET (statement) sets a pixel coordinate to the default color or designated color attribute.
PUT (graphics statement) statement is used to place GET saved or BSAVEd images stored in an array.
SCREEN sets the screen mode of a program. No statement defaults the program to SCREEN 0 text only mode.
STEP (relational statement) is used to step through FOR loop values or use relative graphical coordinates.
VIEW (graphics statement) creates a graphics view port area by defining the coordinate limits to be viewed.
WINDOW (statement) defines the coordinate dimensions of the current graphics viewport.

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Keyboard Input

_CONTROLCHR (statement) OFF allows the control characters to be used as text characters. ON(default) can use them as commands.
_CONTROLCHR (function) returns the current state of _CONTROLCHR as 1 when OFF and 0 when ON.
_EXIT (function) prevents a program user exit and indicates if a user has clicked the close X window button or CTRL + BREAK.
_INPUTBOX$ (function) Displays a prompt in a dialog box, waits for the user to input text or click a button, and returns a string containing the contents of the text box.
_KEYDOWN (function) returns whether modifying keys like CTRL, ALT, SHIFT, and any other keys are pressed.
_KEYHIT (function) returns ASCII one and two byte, SDL Virtual Key and Unicode keyboard key press codes.
_SCREENPRINT (statement) simulates typing text into another OS program using the keyboard.

INKEY$ (function) returns the ASCII string character of a keypress.
INPUT (statement) requests a STRING or numerical keyboard entry from a program user.
INPUT$ (function) used to get a set number of keypress characters or bytes from a file.
INP (function) returns a scan code value from keyboard register &H60(96) to determine key presses.
KEY n (event statement) is used to assign a "softkey" string to a key and/or display them.
KEY(n) (event statement) assigns, enables, disables or suspends event trapping of a keypress.
KEY LIST (statement) lists the 12 Function key soft key string assignments going down left side of screen.
LINE INPUT (statement) requests a STRING keyboard entry from a program user.
ON KEY(n) (event statement) defines a line number or label to go to when a specified key is pressed.
SLEEP (statement) pauses the program for a specified number of seconds or a until a key press.

See also: Keyboard scancodes, ASCII Codes references or Hot Keys for Windows.

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Libraries

_OFFSET (function) returns the memory offset of a variable when used with DECLARE LIBRARY only.
_OFFSET(variable type) can be used store the value of an offset in memory when using DECLARE LIBRARY only.

ALIAS (statement) tells the program that you will use a different name than the name used in the Library file.
BYVAL (statement) used to pass a parameter's value with sub-procedures from a Library.
DECLARE LIBRARY allows the use of OS specific, SDL or C++ external library SUB and FUNCTION procedures
END DECLARE required at the END of the block of Library declarations in QB64.

QB64 also supports $INCLUDE text code file Libraries. QB64 does not support QLB Libraries or OBJ files.

$INCLUDEONCE (metacommand) prevents that include file contents is injected multiple times into a program.

Logical Bitwise Operations

AND (operator) the bit is set when both bits are set.
EQV (operator) the bit is set when both are set or both are not set.
IMP (operator) the bit is set when both are set or both are unset or the second condition bit is set.
OR (operator) the bit is set when either bit is set.
NOT (operator) the bit is set when a bit is not set and not set when a bit is set.
XOR (operator) the bit is set when just one of the bits are set.

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Mathematical Functions and Operations

_CLAMP (function) Forces the given numeric value into a specific range.
_MAX (function) Returns the greater of two given numeric values.
_MIN (function) Returns the lesser of two given numeric values.
_ROUND (function) rounds to the closest EVEN INTEGER, LONG or _INTEGER64 numerical value.

ABS (function) returns the the positive value of a variable or literal numerical value.
ATN (function) or arctangent returns the angle in radians of a numerical tangent value.
CDBL (function) closest double rounding function
CINT (function) closest integer rounding function
CLNG (function) closest long integer rounding function
COS (function) cosine of a radian angle
CSNG (function) closest single rounding function
EXP (function) returns the value of e to the power of the parameter used.
FIX (function) rounds positive or negative values to integer values closer to 0
INT (function) rounds to lower integer value
LOG (function) natural logarithm of a specified numerical value.
SIN (function) sine of a radian angle.
SQR (function) square root of a positive number.
TAN (function) returns the ratio of SINe to COSine or tangent value of an angle measured in radians.

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Memory Handling and Clipboard

_CLIPBOARD$ (function) returns the current STRING contents of the system Clipboard.
_CLIPBOARD$ (statement) sets and overwrites the STRING contents of the current system Clipboard.
_MEM (function) returns _MEM block referring to the largest continuous memory region beginning at a designated variable's offset.
_MEM (variable type) contains read only dot elements for the OFFSET, SIZE, TYPE and ELEMENTSIZE of a block of memory.
_MEMCOPY (statement) copies a value from a designated OFFSET and SIZE TO a block of memory at a designated OFFSET.
_MEMELEMENT (function) returns a _MEM block referring to a variable's memory (but not past it).
_MEMEXISTS (function) verifies that a memory block exists for a memory variable name or returns zero.
_MEMFILL (statement) fills a designated memory block OFFSET with a certain SIZE and TYPE of value.
_MEMFREE (statement) frees a designated memory block in a program. Only free memory once!
_MEMGET (statement) reads a designated value from a designated memory OFFSET
_MEMGET (function) returns a value from a designated memory block and OFFSET using a designated variable TYPE.
_MEMIMAGE (function) returns a _MEM block referring to a designated image handle's memory
_MEMNEW (function) allocates new memory with a designated SIZE and returns a _MEM block referring to it.
_MEMPUT (statement) places a designated value into a designated memory _OFFSET
_MEMSOUND (function) returns a _MEM block referring to a designated sound handle's memory
_OFFSET (function) returns the memory offset of a variable when used with DECLARE LIBRARY or _MEM only.
_OFFSET(%& numerical type) can be used store the value of an offset in memory when using DECLARE LIBRARY or _MEM only.

Functions and statements using QB64's emulated 16 bit memory

DEF SEG (statement) defines the segment address in memory.
PEEK (function) returns the value that is contained at a certain memory address offset.
POKE (statement) sets the value of a specified memory address offset.
SADD (function) returns the address of a STRING variable as an offset from the current data segment.
VARPTR (function) returns an INTEGER value that is the offset pointer of the memory address within it's segment.
VARPTR$ (function) returns a STRING representation of a variable's memory address value
VARSEG (function) returns an INTEGER value that is the segment part of a variable or array memory address.

See also: Screen Memory or Using _OFFSET

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Mouse Input

_AXIS (function) returns a SINGLE value between -1 and 1 indicating the maximum distances from device center 0.
_BUTTON (function) returns -1 when a device button is pressed and 0 when button is released. 2 is the mouse center or scroll button
_BUTTONCHANGE (function) returns -1 when a device button has been pressed and 1 when released. Zero indicates no change.
_DEVICE$ (function) returns a STRING expression listing device names and input types of system input devices.
_DEVICEINPUT (function) returns the _DEVICES number of an _AXIS, _BUTTON or _WHEEL event. Mouse is normally _DEVICEINPUT(2).
_DEVICES (function) returns the number of input devices found on a computer system. The mouse is normally device 2.
_EXIT (function) prevents a program user exit and indicates if a user has clicked the close X window button or CTRL + BREAK.
_LASTAXIS (function) returns the number of axis available on a specified number device listed by _DEVICE$.
_LASTBUTTON (function) returns the number of buttons available on a specified number device listed by DEVICE$.
_LASTWHEEL (function) returns the number of scroll wheels available on a specified number device listed by _DEVICE$.
_MOUSEBUTTON (function) returns whether a specified mouse button number has been clicked. 3 is the mouse center or scroll button
_MOUSEHIDDEN (function) returns the current state of the mouse pointer.
_MOUSEHIDE (statement) hides the OS mouse pointer from view.
_MOUSEINPUT (function) must be used to monitor and read all changes in the mouse status.
_MOUSEMOVE (statement) moves the mouse cursor pointer to a designated coordinate.
_MOUSEMOVEMENTX (function) returns the relative horizontal position of the mouse cursor.
_MOUSEMOVEMENTY (function) returns the relative vertical position of the mouse cursor.
_MOUSESHOW (statement) displays the OS mouse cursor after it has been hidden.
_MOUSEWHEEL (function) returns a positive or negative count the mouse scroll wheel clicks since the last read.
_MOUSEX (function) indicates the current horizontal position of the mouse pointer.
_MOUSEY (function) indicates the current vertical position of the mouse pointer.
_SCREENCLICK simulates clicking the mouse at a position on the screen to get focus.
_WHEEL (function) returns -1 when a device wheel is scrolled up and 1 when scrolled down. Zero indicates no activity.

CALL ABSOLUTE (statement) used to access Interrupt vector &H33 to work with the mouse. Functions 0 to 3 implemented.
INTERRUPT (statement) used to access Interrupt vector &H33 to work with the mouse. Functions 0 to 3 implemented.

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Numerical Manipulation and Conversion

_BIN$ (function) converts the INTEGER part of any value to binary STRING number value.
_CAST (function) performs a C-like cast of a numerical value to a specified numerical type.
_CV (function) used to convert _MK$ ASCII string values to specified numerical value types.
_MK$ (function) converts a specified numerical type into an ASCII string value that must be converted back using _CV.
_PRESERVE (REDIM action) preserves the current contents of an array, when re-dimensioning it.
_TOSTR$ (function) Returns the STRING representation of a numerical value. It's a successor of the legacy STR$ function.
_UNSIGNED {numerical type) defines a numerical value as being positive only using QB64.

ABS (function) returns the the positive value of a variable or literal numerical value.
ASC (function) returns the ASCII code number of a certain STRING text character or a keyboard press.
CDBL (function) converts a numerical value to the closest DOUBLE-precision value.
CHR$ (function) returns the character associated with a certain ASCII character code as a STRING.
CINT (function) returns the closest INTEGER value of a number.
CLEAR (statement) clears all variable values to 0 or null strings and closes all open files.
CLNG (function) rounds decimal point numbers up or down to the nearest LONG integer value.
CSNG (function) converts a numerical value to the closest SINGLE-precision number.
CVD (function) converts STRING values to DOUBLE numerical values.
CVDMBF (function) converts a 8-byte Microsoft Binary format string value to a DOUBLE precision number.
CVI (function) converts 2 byte STRING values to INTEGER numerical values.
CVL (function) converts 4 byte STRING values to LONG numerical values.
CVS (function) converts 4 byte STRING values to SINGLE numerical values.
CVSMBF (function) converts a 4-byte Microsoft Binary format string value to a SINGLE-precision number.
DIM (statement) used to declare a variable type or dimension a STATIC array.
ERASE (array statement) clears a STATIC array of all values and totally removes a $DYNAMIC array.
HEX$ (function) converts the INTEGER part of any value to hexadecimal STRING number value.
INT (function) rounds a numeric value down to the next whole number or INTEGER value.
LEN (function) returns the byte size of strings or numerical variables.
OCT$ (function) converts the INTEGER part of any value to octal STRING number value.
RANDOMIZE (statement) seeds the RND random number generation sequence.
REDIM (statement) re-dimensions the number of elements in a dynamic(resizeable) array.
RND (function) returns a randomly generated number from 0 to .9999999
SGN (function) returns the sign as -1 for negative, zero for 0 and 1 for positive numerical values.
STR$ (function) converts a numerical value to a STRING value.
SWAP (statement) trades the values of two numerical types or strings.
VAL (function) converts number strings into numerical values until it runs into a non-numeric character.

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Port Input and Output (COM and LPT)

GET (file I/O statement) reads port data data by byte or record positions.
LOC (function) finds the current file location or size of a COM port receive buffer.

OPEN COM (statement) opens a computer serial COMmunications port.
OUT (statement) sends values to register or port hardware addresses (emulated - limited access).

PRINT (file statement) writes text and numerical data to a port transmit buffer.
PUT (file I/O statement) writes data into a RANDOM or BINARY port by byte or record position.

See Port Access Libraries for other ways to access COM and LPT ports..

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Print formatting

LPRINT USING (statement) prints template formatted STRING text to an LPT or USB printer page.
PRINT USING (statement) prints template formatted STRING text to the screen.
PRINT USING (file statement) prints template formatted STRING text to a text file.

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Printer Output (LPT and USB)

_PRINTIMAGE (statement) prints an image stretched to the size of the paper setting of an LPT or USB printer.

LPOS (function) returns the current parallel(LPT) printer head position.
LPRINT (statement) prints text to an LPT or USB printer page.
LPRINT USING (statement) prints template formatted STRING text to an LPT or USB printer page.

QB64 will use the default system printer selected. _PRINTIMAGE images will be stretched to the paper size setting.

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Program Flow and Loops

_CONTINUE (statement) skips the remaining lines in a control block (DO/LOOP, FOR/NEXT or WHILE/WEND)
_DEST (statement) sets the current write image or page. All graphics will go to this image.
_DEST (function) returns the current write destination image or page.
_EXIT (function) prevents a user exit and indicates if a user has clicked the close X window button or CTRL + BREAK.
_SOURCE (statement) establishes the image SOURCE using a designated image handle
_SOURCE (function) returns the present image _SOURCE handle value.
_SHELLHIDE (function) returns the code sent by a program exit using END or SYSTEM followed by an INTEGER value.

CALL (statement) sends code execution to a subroutine procedure in a program.
CASE (SELECT CASE statement) used within a SELECT CASE block to specify a conditional value of the compared variable.
CASE ELSE (SELECT CASE statement) used in a SELECT CASE block to specify an alternative to other CASE values.
CASE IS (SELECT CASE statement) used within a SELECT CASE block to specify a conditional value of the compared variable.
DO...LOOP (loop statement) used in programs to repeat code or return to the start of a procedure.
ELSE (statement) used in IF...THEN statements to offer an alternative to other conditional statements.
ELSEIF (statement) used in IF...THEN block statements to offer an alternative conditional statement.
END (statement) ENDs a conditional block statement, a sub-procedure or ends the program with "Press any key..."
END IF (IF statement end) ENDs an IF statement block.
ERROR (error statement) used to simulate an error in a program.
EXIT (statement) exits a loop, function or sub-procedure early.
FOR...NEXT (statement) a counter loop procedure that repeats code a specified number of times.
GOSUB (statement) send the program to a designated line label procedure in the main module or a SUB procedure.
GOTO (statement) sends the program to a designated line number or label.
IF...THEN (statement) a conditional flow statement or block of statements.
LOOP end of a DO...LOOP procedure that repeats code until or while a condition is true.
RESUME (error statement) an error statement that can return the program to the NEXT code line or a specific line number.
RETURN (statement) a sub-procedure statement that returns the program to the code immediately after the procedure call.
RUN (statement) clears and restarts the program currently in memory or executes another specified program.
SELECT CASE (statement) determines the program flow by comparing the value of a variable to specific values.
SHELL (DOS statement) directly accesses the Operating System's command line procedures.
SLEEP (statement) stops program progression for a specific number of seconds or until a keypress is made.
STEP (relational statement) is used to step through FOR loop values or use relative graphical coordinates.
STOP (statement) is used when troubleshooting a program to stop the program at a specified code line.
SYSTEM (statement) immediately exits a program and closes the program window.
UNTIL (conditional statement) continues a DO LOOP procedure until a condition is true.
WHILE (statement) continues a DO LOOP procedure while a condition is true.
WHILE...WEND (statement) a loop procedure that repeats code while a condition is true.

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Sounds and Music

_MIDISOUNDBANK enables _SNDOPEN to use external FM Banks or SoundFonts when playing MIDI files.
$MIDISOUNDFONT (metacommand) (deprecated) enables the MIDI support for _SNDOPEN.
_SNDBAL (statement) sets the balance or 3D position of a sound.
_SNDCLOSE (statement) frees and unloads an open sound using a _SNDOPEN or _SNDCOPY handle.
_SNDCOPY (function) copies a sound to a new handle so that two or more of the same sound can be played at once.
_SNDGETPOS (function) returns the current playing position in seconds of a designated sound handle.
_SNDLEN (function) returns the length of a sound in seconds of a designated sound handle.
_SNDLIMIT (statement) stops playing a sound after it has been playing for a set number of seconds.
_SNDLOOP (statement) loops the playing of a specified sound handle.
_SNDNEW (function) creates a raw empty sound in memory and returns a LONG handle value for later access.
_SNDOPEN (function) loads a sound file with certain capabilities and returns a handle value.
_SNDPAUSE (statement) pauses a specified sound handle if it is playing.
_SNDPAUSED (function) returns the pause status of a specified sound handle.
_SNDPLAY (statement) plays a designated sound file handle.
_SNDPLAYCOPY (statement) copies a sound, plays it, and automatically closes the copy using a handle parameter
_SNDPLAYFILE (statement) a simple command to play a sound file with limited options.
_SNDPLAYING (function) returns whether a sound handle is being played.
_SNDRATE (function) returns the sample rate frequency per second of the current computer's sound card.
_SNDRAW (statement) plays a mono or stereo sound sample frame.
_SNDRAWBATCH (statement) plays a batch of mono or stereo sound sample frames from an array.
_SNDRAWDONE (statement) pads a _SNDRAW stream so the final (partially filled) buffer section is played.
_SNDRAWLEN (function) returns the length, in seconds, of a _SNDRAW sound currently queued.
_SNDOPENRAW (function) returns a handle to a new, separate _SNDRAW audio stream.
_SNDSETPOS (statement) changes the current/starting playing position of a sound in seconds.
_SNDSTOP (statement) stops a playing or paused sound handle.
_SNDVOL (statement) sets the volume of a sound handle being played.
_WAVE (statement) defines the waveform shape for a specified audio channel when used with SOUND or PLAY.

BEEP (statement) makes a beep sound when called or CHR$(7) is printed.
PLAY (music statement) uses a custom string statement to play musical notes.
SOUND (statement) creates sounds of a specified frequency for a set duration.

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String Text Manipulation and Conversion

_CLIPBOARD$ (function) returns the current STRING contents of the system Clipboard.
_CLIPBOARD$ (statement) sets the STRING contents of the current system Clipboard.
_CONTROLCHR (statement) OFF allows the control characters to be used as text characters. ON(default) can use them as commands.
_CONTROLCHR (function) returns the current state of _CONTROLCHR as 1 when OFF and 0 when ON.
_CV (function) used to convert _MK$ ASCII string values to numerical values.
_MK$ (function) converts any numerical type into an ASCII string value that must be converted back using _CV.
_STRCMP (function) compares the relationship between two strings.
_STRICMP (function) compares the relationship between two strings, without regard for case-sensitivity.
_TOSTR$ (function) Returns the STRING representation of a numerical value. It's a successor of the legacy STR$ function.

ASC (statement) allows a QB64 program to change a character at any position of a predefined STRING.
HEX$ (function) returns the base 16 hexadecimal representation of an INTEGER value as a STRING.
INSTR (function) searches for the first occurance of a search STRING within a string and returns the position.
LCASE$ (function) changes the uppercase letters of a STRING to lowercase.
LEFT$ (function) returns a part of a STRING from the start a designated number of character places.
LEN (function) returns the number of bytes or characters in a STRING value.
LSET (statement) left-justifies a fixed length string expression based on the size of the STRING.
LTRIM$ (function) returns a string with all leading spaces removed.
MID$ (statement) allows a QB64 program to change existing characters of a predefined STRING.
MKD$ (function) converts a DOUBLE numerical value into an 8 byte ASCII STRING value.
MKDMBF$ (function) converts a double-precision number to a string containing a value in Microsoft Binary format.
MKI$ (function) converts a numerical INTEGER value to a 2 byte ASCII string value.
MKL$ (function) converts a numerical LONG value to a 4 byte ASCII string value.
MKS$ (function) converts a numerical SINGLE value to a 4 byte ASCII string value.
MKSMBF$ (function) converts a single-precision number to a string containing a value in Microsoft Binary format.}}
OCT$ (function) returns the base 8 Octal representation of an INTEGER value.
RIGHT$ (function) returns a set number of characters in a STRING variable starting from the end.
RSET (statement) right-justifies a string according to length of the string expression.
RTRIM$ (function) returns a string with all of the spaces removed at the right end of a string.
SPACE$ (function) returns a STRING consisting of a number of space characters.
STR$ (function) converts a numerical value to a STRING.
STRING ($ variable type) one byte text variable with ASCII code values from 0 to 255.
STRING$ (function) returns a STRING consisting of a single character repeated a set number of times.
SWAP (statement) used to exchange two string variable or array element values.
UCASE$ (function) returns a string with all letters as uppercase.
VAL (function) converts a string number value to a numerical value.

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Sub procedures and Functions

CALL (statement) sends code execution to a SUB procedure in a program. Parameter brackets are required when used.
CALL ABSOLUTE (statement) used to access Interrupts on the computer or execute assembly type procedures.
CHAIN (statement) changes seamlessly from one program module to another.
DECLARE (BASIC statement) used to tell that a SUB or FUNCTION is created to be used in the program. NOT USED by QB64!
END (statement) ends a SUB or FUNCTION procedure.
EXIT (statement) exits a SUB or FUNCTION procedure early.
FUNCTION (statement) a procedure that holds ONE return value in the function's name which is a variable type.
GOSUB (statement) sends the program to a sub program that uses a line number or label.
$INCLUDE (metacommand) used to insert a source code text file into your program at the point of the insertion.
INTERRUPT (statement) a built in assembly routine for accessing computer information registers.
RETURN (statement) used in GOSUB procedures to return to the original call code line.
RUN (statement) flow statement that clears and restarts the program currently in memory or executes another specified program.
SHARED (statement) defines a variable or list of variables as shared with the main program module.}}
SHELL (statement) allows a program to use OS command lines.
STATIC (statement) defines a variable or list of variables that will retain their values after the sub-procedure is exited.
SUB (statement) procedures are programs within programs that can return multiple calculations.

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TCP/IP Networking HTTP(S) and Email

_CONNECTED (function) returns the connection status of a TCP/IP connection handle.
_CONNECTIONADDRESS$ (function) function returns a connected user's STRING IP address value.
_STATUSCODE (function) gives the HTTP status code of an HTTP response that was opened using _OPENCLIENT.

_OPENCLIENT (function) connects to a Host on the Internet as a Client and returns the Client status handle.
_OPENCONNECTION (function) open's a connection from a client that the host has detected and returns a status handle.
_OPENHOST (function) opens a Host which listens for new connections and returns a Host status handle.

_ENCODEURL$ (function) returns the so called percent encoded representation of the given URL.
_DECODEURL$ (function) returns the decoded plain text URL of the given encoded URL.

CLOSE (statement) closes an opened internet connection using the handle assigned in an OPEN statement.

GET (HTTP statement) reads the response of an HTTP request that was opened using _OPENCLIENT.
GET (TCP/IP statement) reads a TCP/IP connection port to return a value.

PUT (TCP/IP statement) sends unformatted(raw) data to an open connection using a user's handle.

Text on Screen

_CONTROLCHR OFF allows ASCII characters 0 to 31 to be used as text characters. ON(default) resets to default usage.
_FONT (function) creates a new alphablended font handle from a designated image handle
_FONT (statement) sets the current _LOADFONT function font handle to be used by PRINT or _PRINTSTRING.
_MAPUNICODE (statement) maps a Unicode value to an ASCII character code value.
_PRINTSTRING (statement) prints text or custom font strings using graphic column and row coordinate positions.
_SCREENPRINT (statement) simulates typing text into a Windows program using the keyboard.
_TOSTR$ (function) Returns the STRING representation of a numerical value. It's a successor of the legacy STR$ function.
_UCHARPOS (function) calculates the starting pixel positions of every character of a (unicode) text string.
_UPRINTSTRING (statement) locates and prints a (unicode) text string using graphic coordinates.

CHR$ (function) returns the text character associated with a certain ASCII character code as a one byte STRING.
CLS (statement) clears a screen page or the program SCREEN. QB64 can clear with a color.
COLOR (statement) used to change the color of the text and background in some legacy screen modes.
CSRLIN (function) returns the current print cursor row position on the screen.
INPUT (statement) requests a STRING or numerical keyboard entry from a program user.
KEY LIST (statement) vertically lists all the ON KEY(n) softkey strings associated with each function key F1 to F12.
LINE INPUT (statement) requests a STRING keyboard entry from a program user.
LOCATE (statement) locates the screen text row and column positions for a PRINT or INPUT procedure.
POS (function) returns the current print cursor column position.
PRINT (statement) prints numeric or string expressions to the program screen.
PRINT USING (statement) prints template formatted numeric or string values to the program screen.
SCREEN (statement) sets the screen mode of a program. No statement defaults the program to SCREEN 0 text mode.
SCREEN (function) returns the ASCII code of a text character or the color attribute at a set text location on the screen.
SPACE$ (function) returns a string consisting of a number of space characters.
SPC (function) used in PRINT and LPRINT statements to print or output a number of space characters.
STR$ (function) returns the STRING representation of a numerical value.
STRING$(function) returns a STRING consisting of a single character repeated a set number of times.
TAB (function) used in PRINT and LPRINT statements to move to a specified text column position.
VIEW PRINT (statement) defines the boundaries of a text viewport PRINT area.
WIDTH (statement) changes the text dimensions of certain SCREEN modes or printer page widths
WRITE (screen I/O statement) writes a comma-separated list of values to the screen.

See also: Fonts and Unicode or ASCII Code Table

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Time, Date and Timing

_AUTODISPLAY (statement) enables the automatic display of the screen image changes previously disabled by _DISPLAY.
_DELAY (statement) suspends program execution for a SINGLE value of seconds down to milliseconds.
_DISPLAY (statement) turns off automatic display while only displaying the screen changes when called.
_FREETIMER (function) returns a free TIMER number for multiple ON TIMER(n) events.
_KEYDOWN (function) returns whether modifying keys like CTRL, ALT, SHIFT, and any other keys are pressed.
_KEYHIT (function) returns ASCII one and two byte, SDL Virtual Key and Unicode keyboard key press codes.
_LIMIT (statement) sets the loop repeat rate of a program to so many per second, relinquishing spare cpu cycles.

DATE$ (function) returns the present computer date in a mm-dd-yyyy string format

INKEY$ (function) can be used in a loop to wait for a keypress or a [Ctrl] + letter key combination.
INPUT (statement) can be used to wait for an [Enter] key press or a text or numerical menu entry.
INPUT$ (function) can be used to wait for a key press or a fixed length text entry.
ON KEY(n) (event statement) executes when a keypress or keypress combination occurs.
ON TIMER(n) (event statement) executes when a timed event occurs. QB64 can use multiple numbered timer events.

SLEEP (statement) pauses the program for a specified number of seconds or a until a key press is made.
TIME$ (function) returns the present computer time in a hh:mm:ss 24 hour string format

TIMER (function) returns the number of seconds past the previous midnite down to a QB64 accuracy of one millisecond.
TIMER (statement) enables, turns off or stops timer event trapping. In QB64 TIMER(n) FREE can free multiple timers.

WAIT (statement) normally used to delay program display execution during or after vertical retrace periods.

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Window and Desktop

_COLORCHOOSERDIALOG (function) Displays a standard color picker dialog box and returns a 32-bit RGBA color selected by the user.
_DESKTOPHEIGHT (function) returns the height of the desktop (not program window).
_DESKTOPWIDTH (function) returns the width of the desktop (not program window).
_FULLSCREEN (function) returns the present full screen mode setting number of the screen window.
_FULLSCREEN (statement) sets the full screen mode of the screen window. Alt + Enter can do it manually.
_HEIGHT (function) returns the height of a _SCREENIMAGE handle to get the desktop resolution.
_ICON (statement) creates a program icon from an image file handle created by _LOADIMAGE. Cannot use .ICO files!
_INPUTBOX$ (function) Displays a prompt in a dialog box, waits for the user to input text or click a button, and returns a string containing the contents of the text box.
_MESSAGEBOX (function) Displays a message dialog box, which presents a message and returns the button ID clicked by the user.
_MESSAGEBOX (statement) Displays a message dialog box, which presents a message to the user.
_NEWIMAGE (statement) function prepares a window image surface and returns the handle value.
_NOTIFYPOPUP (statement) Shows a system notification popup.
_OPENFILEDIALOG$ (function) Displays a standard dialog box that prompts the user to open a file.
$RESIZE (metacommand) used with ON allows a user to resize the program window where OFF does not.
_RESIZE (function) returns -1 when a program user attempts to resize the program screen.
_RESIZEHEIGHT (function) returns the requested new user screen height when $RESIZE:ON allows it.
_RESIZEWIDTH (function) returns the requested new user screen width when $RESIZE:ON allows it.
_SAVEFILEDIALOG$ (function) Displays a standard dialog box that prompts the user to save a file.
_SCREENCLICK simulates clicking the mouse at a position on the screen to get focus.
_SCREENEXISTS (function) returns a -1 value once a screen has been created.
$SCREENHIDE (metacommand) hides the program window throughout the program until $SCREENSHOW is used.
_SCREENHIDE (statement) hides the main program window in a section of code until _SCREENSHOW is used.
_SCREENIMAGE (function) creates an image of the current desktop and returns an image handle.
_SCREENMOVE (statement) positions the program window on the desktop using designated coordinates or _MIDDLE.
_SCREENPRINT (statement) simulates typing text into a Windows program using the keyboard.
$SCREENSHOW (metacommand) displays the main program window throughout the program after $SCREENHIDE.
_SCREENSHOW (statement) displays the main program window in a section of code after _SCREENHIDE has been used.
_SCREENX (function) returns the current program window's upper left corner column position on the desktop.
_SCREENY (function) returns the current program window's upper left corner row position on the desktop.
_SELECTFOLDERDIALOG$ (function) Displays a dialog box that enables the user to select a folder (directory).
_SMOOTH (function) checks whether the current _FULLSCREEN mode has antialiasing enabled or not.
_TITLE (statement) sets the program name string in the title bar of the program window.
_WIDTH (function) returns the width of a _SCREENIMAGE handle to get the desktop resolution.

SCREEN sets the screen mode of a program. No statement defaults the program to SCREEN 0 text mode.

See also: Console Window, Windows Hot Keys or Focus on Program.

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QB64 Programming Symbols

[Note: All symbols below can also be used inside of literal quoted strings except for quotation marks.]

Print, Input or File Formatting

; Semicolon after a PRINT stops the invisible cursor at end of the printed value. Can prevent screen rolling!
, Comma after a PRINT tabs the invisible cursor past the end of the printed value.
" Quotation mark delimits the ends of a literal STRING value in a PRINT, INPUT or LINE INPUT statement.
? Question mark is a shortcut substitute for the PRINT keyword. Will change to PRINT when cursor leaves the code line.

Program Code Markers

' Apostrophe denotes a program comment, to ignore a code line or a legacy QBasic Metacommand. Same as using REM.
, Comma is a statement variable or DATA, SUB or FUNCTION parameter separator.
Colons can be used to separate two procedure statements on one code line.
$ Dollar sign used as prefix denotes a Metacommand, used as suffix it denotes a STRING variable.
( ) Parenthesis enclose a math or conditional procedure order, SUB or FUNCTION parameters or to pass by value.
+ Plus concatenation operator MUST be used to combine literal string values in a variable definition.
" Quotation mark delimits the ends of a literal STRING value. Use CHR$(34) to insert quotes in a text STRING.
REM or apostrophe are used to make comments or ignore code or precedes a legacy QBasic Metacommand.
_ Underscore at the end of a code line is used to continue a line of code to the next program line in QB64 only.

(Return to Table of Contents)

Variable Name Type Suffixes

$ STRING text character type: 1 byte
! SINGLE floating decimal point numerical type (4 bytes)
# DOUBLE floating decimal point numerical type (8 bytes)
## _FLOAT QB64 decimal point numerical type (32 bytes)
~ _UNSIGNED QB64 whole positive numerical type when it precedes the 6 numerical suffixes below:
% INTEGER whole numerical type (2 bytes)
& LONG whole numerical type (4 bytes}
&& _INTEGER64 QB64 whole numerical type (8 bytes)
` _BIT QB64 whole numerical type (1 bit)(Key below tilde(~) or CHR$(96))
%% _BYTE QB64 whole numerical type (1 byte)
%& _OFFSET QB64 whole numerical pointer address type (any byte size required)

(Return to Table of Contents)

Numerical Base Prefixes

&B Binary base 2 Digits 0 or 1 [QB64]
&O Octal base 8 Digits 0 to 7
&H Hexadecimal base 16: Digits 0 to F

Mathematical Operations

+ Addition operator or sign
- Subtraction operator or sign
* Multiplication operator
/ Division (floating decimal point) operator
\ Integer division operator
^ Exponential operator
MOD Integer Remainder division operator

Relational Operations

= (Equal to condition)
> (Greater than condition)
< (Less than condition)
<> (Not equal to condition)
>= (Greater than or equal to condition)
<= (Less than or equal to condition)

(Return to Table of Contents)

QB64 Programming References

Wiki Pages Main Page with Articles and Tutorials QB64 specific keywords (alphabetical) Original QBasic keywords (alphabetical) QB64 OpenGL keywords (alphabetical) Keywords by Usage Got a question about something? Frequently Asked Questions about QB64 QB64 Phoenix Edition Community Forum Links to other QBasic Sites: Pete's QBasic Forum Pete's QBasic Downloads

@@ Line 124: / Line 124: @@
 * [[AND (boolean)]] {{Text|returns True if all of the arguments are True.}}
 * [[_ANDALSO]] (boolean) {{Text|performs short-circuiting logical conjunction on two expressions.}}
-* [[_IIF]] (pseudo-function) {{Text|provides conditional evaluations similar to a ternary operator, with short-circuiting behavior.}}
+* [[_IIF]] (function) {{Text|provides conditional evaluations similar to a ternary operator, with short-circuiting behavior.}}
 * [[_NEGATE]] (boolean) {{Text|returns True when a [[boolean]] evaluation is False and vice-versa.}}
 * [[NOT]] (boolean) {{Text|returns the opposite condition of an argument.}}
@@ Line 220: / Line 220: @@
-== Error Trapping ==
+== Error Trapping, Logging & Debugging ==
+* [[$ASSERTS]] (metacommand) {{Text|Enables the [[_ASSERT]] macro}}
+* [[$CHECKING]] (metacommand) {{Text|turns off or on error event checking and strips error code from compiled programs.}}
+* [[$DEBUG]] (metacommand) {{Text|enables debugging features, allowing you to step through your code line by line.}}
 * [[_ASSERT]] (statement) {{Text|Performs debug tests.}}
-* [[$ASSERTS]] (metacommand) {{Text|Enables the [[_ASSERT]] macro}}
-* [[$CHECKING]] (metacommand) {{Text|turns off or on error event checking and strips error code from compiled programs.}}
 * [[_ERRORLINE]] (function) {{Text|returns the actual text code line where a program error occurred.}}
+* [[_LOGERROR]] (statement) {{Text|writes a log message at the Error level with an accompanying stacktrace.}}
+* [[_LOGINFO]] (statement) {{Text|writes a log message at the Information level.}}
+* [[_LOGMINLEVEL]] (function) {{Text|returns the current minimum logging level that is being output.}}
+* [[_LOGTRACE]] (statement) {{Text|writes a log message at the Trace level.}}
+* [[_LOGWARN]] (statement) {{Text|writes a log message at the Warning level.}}
 * [[ERR]] (function) {{Text|returns the error code number of the last error to occur.}}
 * [[ERROR]] (statement) {{Text|simulates a program error based on the error code number used.}}
@@ Line 232: / Line 241: @@
 * [[ON ERROR]] (statement) [[GOTO]] {{Text|sends the program to a line number or label when an error occurs. Use to avoid program errors.}}
 * [[RESUME]] (statement) {{Text|error statement sends the program to the [[NEXT]] code line or a designated line number or label .}}
 <p style="text-align: center">([[#toc|Return to Table of Contents]])</p>
@@ Line 609: / Line 617: @@
 * [[_BIN$]] (function) {{Text|converts the [[INTEGER]] part of any value to binary [[STRING]] number value.}}
+* [[_CAST]] (function) {{Text|performs a C-like cast of a numerical value to a specified numerical type.}}
 * [[_CV]] (function)  {{Text|used to convert [[_MK$]] [[ASCII]] [[STRING|string]] values to specified numerical value types.}}
 * [[_MK$]] (function)  {{Text|converts a specified numerical type into an [[ASCII]] [[STRING|string]]  value that must be converted back using [[_CV]].}}

Keyword Reference - By usage: Difference between revisions

Latest revision as of 20:21, 8 December 2024

Contents

Arrays and Data Storage

Colors and Transparency

Console Window

Conditional Operations

Definitions and Variable Types

External Disk and API calls

Error Trapping, Logging & Debugging

Event Trapping

File Input and Output

Checksums and Hashes

Fonts

Game Controller Input (Joystick)

Graphic Commands

Graphics and Imaging:

Keyboard Input

Libraries

Logical Bitwise Operations

Mathematical Functions and Operations

Memory Handling and Clipboard

Mouse Input

Numerical Manipulation and Conversion

Port Input and Output (COM and LPT)

Print formatting

Printer Output (LPT and USB)

Program Flow and Loops

Sounds and Music

String Text Manipulation and Conversion

Sub procedures and Functions

TCP/IP Networking HTTP(S) and Email

Text on Screen

Time, Date and Timing

Window and Desktop

QB64 Programming Symbols

QB64 Programming References

Navigation menu

Keyword Reference - By usage: Difference between revisions

Latest revision as of 20:21, 8 December 2024

Arrays and Data Storage

Colors and Transparency

Console Window

Conditional Operations

Definitions and Variable Types

External Disk and API calls

Error Trapping, Logging & Debugging

Event Trapping

File Input and Output

Checksums and Hashes

Fonts

Game Controller Input (Joystick)

Graphic Commands

Graphics and Imaging:

Keyboard Input

Libraries

Logical Bitwise Operations

Mathematical Functions and Operations

Memory Handling and Clipboard

Mouse Input

Numerical Manipulation and Conversion

Port Input and Output (COM and LPT)

Print formatting

Printer Output (LPT and USB)

Program Flow and Loops

Sounds and Music

String Text Manipulation and Conversion

Sub procedures and Functions

TCP/IP Networking HTTP(S) and Email

Text on Screen

Time, Date and Timing

Window and Desktop

QB64 Programming Symbols

QB64 Programming References

Navigation menu

Search