Delete public and private memory variables


      RELEASE <idMemvar list>
         RELEASE ALL [LIKE | EXCEPT <skeleton>]


<idMemvar list> is a list of private or public variables or arrays to delete.

ALL [LIKE|EXCEPT <skeleton>] defines the set of visible private memory variables to assign, or to exclude from assignment of, a NIL value. <skeleton> is the wildcard mask to specify a group of memory variables to delete. The wildcard characters supported are * and ?.


RELEASE is a memory variable command that performs one of two actions depending on how it is specified. If RELEASE is specified with <idMemvar list>, the specified public and private memory variables and/or arrays are deleted from memory. Previous hidden instances (public or private variables defined in higher-level procedures) become accessible upon termination of the procedure where the variable was originally created.

If RELEASE is specified with any form of the ALL clause, private memory variables created at the current procedure level are assigned a NIL and not deleted until the current procedure or user-defined function terminates. Public variables are unaffected by this form of the RELEASE command. To release public variables, you must RELEASE them explicitly or use CLEAR MEMORY.

Local or static variables are not affected by the RELEASE command. Local variables are released automatically when the procedure or user- defined function (where the variables were declared) terminates. Static variables cannot be released since they exist for the duration of the program.





Close a specific set of files


      CLOSE [<idAlias> | ALL | ALTERNATE | DATABASES |
             FORMAT | INDEXES]


<idAlias> specifies the work area where all files are to be closed.

ALL closes alternate, database, and index files in all work areas, releasing all active filters, relations, and format definitions.

ALTERNATE closes the currently open alternate file, performing the same action as SET ALTERNATE TO with no argument.

DATABASES closes all open databases, memo and associated index files in all work areas, and releases all active filters and relations. It does not, however, have any effect on the active format.

FORMAT releases the current format, performing the same action as SET FORMAT TO with no argument.

INDEXES closes all index files open in the current work area.


CLOSE is a general purpose command that closes various types of Clipper files depending on the specified option. CLOSE with no option closes the current database and associated files, the same as USE with no arguments.

In Harbour, a number of other commands also close files including:

          .  QUIT
          .  CANCEL*
          .  RETURN from the highest level procedure
          .  CLEAR ALL*
          .  USE with no argument





Terminate program processing


      CANCEL* | QUIT


CANCEL and QUIT both terminate the current program, closing all open files, and returning control to the operating system. You can use either command from anywhere in a Clipper program system. A RETURN executed at the highest level procedure performs the same action. Note that CANCEL is a compatibility command. QUIT should be used in its place.


. Return code: When a Clipper program terminates, the return code is set to 1 if the process ends with a fatal error. If the process ends normally, the return code is set to 0 or the last ERRORLEVEL() set in the program.













Terminates an application.






This function terminates the current application and returns to the system.


      PROCEDURE EndApp( lYesNo )
         IF lYesNo




 Terminate program processing



     QUIT and CANCEL both terminate program processing, close all open files,
     and return control to the operating system.  Each of these commands can
     be used from anywhere in a program system.  A RETURN executed at the
     highest level procedure or a BREAK, with no pending SEQUENCE, also QUITs
     the program.


     .  Return code: When a Clipper program terminates, the return
        code is set to 1 if the process ends with a fatal error.  If the
        process ends normally, the return code is set to zero or the last
        ERRORLEVEL() set in the program.


     .  This example uses QUIT in a dialog box:

        IF DialogYesNo(10, 10, "Quit to DOS", "BG+/B,B/W", 2)

 Files:     Library is CLIPPER.LIB.


C5 Commands

 ?|??            Display one or more values to the console
 @...BOX         Draw a box on the screen
 @...CLEAR       Clear a rectangular region of the screen
 @...GET         Create a new Get object and display it
 @...PROMPT      Paint a menu item and define a message
 @...SAY         Display data at a specified screen or printer row and column
 @...TO          Draw a single- or double-line box
 ACCEPT*         Place keyboard input into a memory variable
 APPEND BLANK    Add a new record to the current database file
 APPEND FROM     Import records from a database (.dbf) file or ASCII text file
 AVERAGE         Average numeric expressions in the current work area
 CALL*           Execute a C or Assembler procedure
 CANCEL*         Terminate program processing
 CLEAR ALL*      Close files and release public and private variables
 CLEAR GETS      Release Get objects from the current GetList array
 CLEAR MEMORY    Release all public and private variables
 CLEAR SCREEN    Clear the screen and return the cursor home
 CLEAR TYPEAHEAD Empty the keyboard buffer
 CLOSE           Close a specific set of files
 COMMIT          Perform a solid-disk write for all active work areas
 CONTINUE        Resume a pending LOCATE
 COPY FILE       Copy a file to a new file or to a device
 COPY STRUCTURE  Copy the current .dbf structure to a new database (.dbf) file
 COPY STRU EXTE  Copy field definitions to a .dbf file
 COPY TO         Export records to a database (.dbf) file or ASCII text file
 COUNT           Tally records to a variable
 CREATE          Create an empty structure extended (.dbf) file
 CREATE FROM     Create a new .dbf file from a structure extended file
 DELETE          Mark records for deletion
 DELETE FILE     Remove a file from disk
 DELETE TAG      Delete a tag
 DIR*            Display a listing of files from a specified path
 DISPLAY         Display records to the console
 EJECT           Advance the printhead to top of form
 ERASE           Remove a file from disk
 FIND*           Search an index for a specified key value
 GO              Move the pointer to the specified identity
 INDEX           Create an index file
 INPUT*          Enter the result of an expression into a variable
 JOIN            Create a new database file by merging from two work areas
 KEYBOARD        Stuff a string into the keyboard buffer
 LABEL FORM      Display labels to the console
 LIST            List records to the console
 LOCATE          Search sequentially for a record matching a condition
 MENU TO         Execute a lightbar menu for defined PROMPTs
 NOTE*           Place a single-line comment in a program file
 PACK            Remove deleted records from a database file
 QUIT            Terminate program processing
 READ            Activate full-screen editing mode using Get objects
 RECALL          Restore records marked for deletion
 REINDEX         Rebuild open indexes in the current work area
 RELEASE         Delete public and private memory variables
 RENAME          Change the name of a file
 REPLACE         Assign new values to field variables
 REPORT FORM     Display a report to the console
 RESTORE         Retrieve memory variables from a memory (.mem) file
 RESTORE SCREEN* Display a saved screen
 RUN             Execute a DOS command or program
 SAVE            Save variables to a memory (.mem) file
 SAVE SCREEN*    Save the current screen to a buffer or variable
 SEEK            Search an order for a specified key value
 SELECT          Change the current work area
 SET ALTERNATE   Echo console output to a text file
 SET BELL        Toggle sounding of the bell during full-screen operations
 SET CENTURY     Modify the date format to include or omit century digits
 SET COLOR*      Define screen colors
 SET CONFIRM     Toggle required exit key to terminate GETs
 SET CONSOLE     Toggle console display to the screen
 SET CURSOR      Toggle the screen cursor on or off
 SET DATE        Set the date format for input and display
 SET DECIMALS    Set the number of decimal places to be displayed
 SET DEFAULT     Set the CA-Clipper default drive and directory
 SET DELETED     Toggle filtering of deleted records
 SET DELIMITERS  Toggle or define GET delimiters
 SET DESCENDING  Change the descending flag of the controlling order
 SET DEVICE      Direct @...SAYs to the screen or printer
 SET EPOCH       Control the interpretation of dates with no century digits
 SET ESCAPE      Toggle Esc as a READ exit key
 SET EXACT*      Toggle exact matches for character strings
 SET EXCLUSIVE*  Establish shared or exclusive USE of database files
 SET FILTER      Hide records not meeting a condition
 SET FIXED       Toggle fixing of the number of decimal digits displayed
 SET FORMAT*     Activate a format when READ is executed
 SET FUNCTION    Assign a character string to a function key
 SET INDEX       Open one or more order bags in the current work area
 SET INTENSITY   Toggle enhanced display of GETs and PROMPTs
 SET KEY         Assign a procedure invocation to a key
 SET MARGIN      Set the page offset for all printed output
 SET MEMOBLOCK   Change the block size for memo files
 SET MESSAGE     Set the @...PROMPT message line row
 SET OPTIMIZE    Change the setting that optimizes using open orders
 SET ORDER       Select the controlling order
 SET PATH        Specify the CA-Clipper search path for opening files
 SET PRINTER     Toggle echo of output to printer or set the print destination
 SET PROCEDURE*  Compile procedures and functions into the current object file
 SET RELATION    Relate two work areas by a key value or record number
 SET SCOPE       Change the boundaries for scoping keys in controlling order
 SET SCOPEBOTTOM Change bottom boundary for scoping keys in controlling order
 SET SCOPETOP    Change top boundary for scoping keys in controlling order
 SET SCOREBOARD  Toggle the message display from READ or MEMOEDIT()
 SET SOFTSEEK    Toggle relative seeking
 SET TYPEAHEAD   Set the size of the keyboard buffer
 SET UNIQUE*     Toggle inclusion of non-unique keys into an index
 SET WRAP*       Toggle wrapping of the highlight in menus
 SKIP            Move the record pointer to a new position
 SORT            Copy to a database (.dbf) file in sorted order
 STORE*          Assign a value to one or more variables
 SUM             Sum numeric expressions and assign results to variables
 TEXT*           Display a literal block of text
 TOTAL           Summarize records by key value to a database (.dbf) file
 TYPE            Display the contents of a text file
 UNLOCK          Release file/record locks set by the current user
 UPDATE          Update current database file from another database file
 USE             Open an existing database (.dbf) and its associated files
 WAIT*           Suspend program processing until a key is pressed
 ZAP             Remove all records from the current database file


Basic Controls – 1

( Image, Label and Button )

We are continuing with Viva_HMG.hbp, Main.prg and Main.fmg. First, let’s enlarge our form: width: 650, height: 550; and then place an image: First click “image” button the toolbar of HMG-IDE, and then click anywhere in the form. This clicked point in the form, will be left upper corner of control; in this case : image. IDE always first places controls with its default values. Our image is 405 x 340 pixel size:

We need assign a size to image control so it can hold properly our image. We can manually set these values and assign name of image file:

Background color of our form didn’t well-matched with this image. Let’s change it to white:

In this step, if we run the program we will see like this :

The STRETCH option of IMAGE control allows assigning size values to the control other than original image sizes. In this case quality of image may decrease. We need also avoiding distortion too; that is keeping fixed aspect ratio of image.

By assigning same width / height values of form and image; we can use an image as back-ground image of form. But in this case we can’t place other control onto image: because controls must not be overlap to each other. Under certain circumstances system not obstructs this. But the beneath control can’t seen.

The LABEL control is an exception of this rule by TRANSPARENT option. If a label is transparent, the beneath control may be seen partially.

Let’s add a label to our form:

The big “A” symbol in the toolbar of IDE represent LABEL. First click this button and then top of our form:

The placeholder of LABEL is primitive situation for now. We have added a new and adjusted  both to our needs:

If we built and run our project after set these values, appearance will be like this:

Since two controls (labels) have been overlapped, constructing this “shadow” effect will be a few painful. You can edit .fmg file out of HMG, via any text editor when necessary.

Labels probably are most used controls in GUI programming. This control simply displays any text onto form. For xBase programmers we can say this is GUI counterpart of @ …,… SAY command. As all other GUI controls, we use coordinate system to indicate placement of control. In addition we can set size ( width, height ), back and fore color values, font properties and others as well as we need.

Labels also have ALIGNEMENT property with LEFT, RIGHT and CENTER option. In this sample used LEFT.

In addition, LABEL control supports ACTION event too. This means you can instruct a LABEL control to do an action when user clicked it; same as BUTTON.

Last control to use in this sample is button.

Beside menus, buttons are handy controls for doing an action when user clicked. Let’s see how :

The button for BUTTON in the IDE Tool Bar is this:

As precedents, one click to this button and another one to form, under image:

And two more :

Now we can tailor these buttons to our needs:

First let’s change names and captions given by IDE:

btnOpenFile, btnEditRec and btnExit to names and Open File, Edit Record and Exit to captions, consecutively:

It’s time to assign ACTIONs to this buttons.

MsgInfo( “Open File”) to ACTION of btnOpenFile

MsgInfo( “Edit Record”) to ACTION of , btnEditRec,

ThisWindow.Release to ACTION of btnExit.

And, RUN of course …

Test ACTIONs of buttons by clicking: first two will repeat the sentences in their captions via MsgInfo() function  and the last will terminate program. Yes, we are using RELEASE method to the main window for terminate running program, instead of QUIT or CANCEL commands.

That’s all for now !

Downloads source files

C5 Flow Control Commands, Statements and Funtions

Commands :


Execute a C or Assembler procedure

CALL <idProcedure> [WITH <exp list>]


Terminate program processing


DO* :

Call a procedure

DO <idProcedure> [WITH <argument list>]


Terminate program processing



Execute a DOS command or program

RUN | !* <xcCommandLine>


Assign a procedure invocation to a key

SET KEY <nInkeyCode> TO [<idProcedure>]


Compile procedures/functions into the current .OBJ file

SET PROCEDURE TO [<idProgramFile>[.<ext>]]


Suspend program processing until a key is pressed

WAIT [<expPrompt>] [TO <idVar>]

Statements :


Declare a module identifier

ANNOUNCE <idModule>


Define a sequence of statements for a BREAK

    [BREAK [<exp>]]
    [RECOVER [USING <idVar>]]


Execute one of several alternative blocks of statements

   CASE <lCondition1>
   [CASE <lCondition2>]


Execute a loop while a condition is true (.T.)

[DO] WHILE <lCondition>


Declare an exit procedure

EXIT PROCEDURE <idProcedure>
    [FIELD <idField list> [IN <idAlias>]]
    [LOCAL <identifier> [[:= <initializer>]]]
    [MEMVAR <identifer list>]
    . <executable statements>


Declare a list of procedure or user-defined function names

EXTERNAL <idProcedure list>


Execute a block of statements a specified number of times

FOR <idCounter> := <nStart> TO <nEnd> [STEP <nIncrement>]


Declare a user-defined function name and formal parameters

[STATIC] FUNCTION <idFunction>[(<idParam list>)]
    [LOCAL <identifier> [[:= <initializer>], ... ]]
    [STATIC <identifier> [[:= <initializer>], ... ]]
    [FIELD <identifier list> [IN <idAlias>]]
    [MEMVAR <identifier list>]
    . <executable statements>
RETURN <exp>

IF :

Execute one of several alternative blocks of statements

IF <lCondition1>
[ELSEIF <lCondition2>]


Declare an initialization procedure

INIT PROCEDURE <idProcedure> [(<idParam list>)]
    [FIELD <idField list> [IN <idAlias>]]
    [LOCAL <identifier> [[:= <initializer>]]]
    [MEMVAR <identifer list>]
    . <executable statements>


Place a single-line comment in a program file

NOTE This is a comment line


Create private parameter variables

PARAMETERS <idPrivate list>


Declare a procedure name and formal parameters

[STATIC] PROCEDURE <idProcedure> [(<idParam list>)]
    [FIELD <idField list> [IN <idAlias>]
    [LOCAL <identifier> [[:= <initializer>], ... ]]
    [MEMVAR <identifier list>]
    [STATIC <identifier> [[:= <initializer>], ... ]]
    . <executable statements>


Declare a module request list

REQUEST <idModule list>


Terminate a procedure, user-defined function or program

RETURN [<exp>]

Functions :


Branch out of a BEGIN SEQUENCE…END construct

BREAK(<exp>) --> NIL

EVAL() :

Evaluate a code block

EVAL(<bBlock>, [<BlockArg list>]) --> LastBlockValue

IF() :

Return the result of an expression based on a condition

[I]IF(<lCondition>, <expTrue>, <expFalse>) --> Value


Determine the position of the last actual parameter passed

PCOUNT() --> nLastArgumentPos


Assign an action block to a key

SETKEY(<nInkeyCode>, [<bAction>]) --> bCurrentAction


Toggle Alt-C and Ctrl-Break as program termination keys

SETCANCEL([<lToggle>]) --> lCurrentSetting

WORD()* :

Convert CALL command numeric parameters from double to int

WORD(<nNumber>) --> NIL