Harbour All Functions – O

OctalToDec

ordBagExt
ordBagName
ordCondSet
ordCreate
ordDestroy
ordFor
ordKey

OS

OutErr
OutStd

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Harbour Terminal Functions

Alert
Col
DevOutPict
HB_ColorIndex
HB_EOL
MaxCol
MaxRow
OutErr
OutStd

SayScreen

Row

HB_EOL()

HB_EOL()

Returns the newline character(s) to use with the current OS

Syntax

      hb_eol() --> cString

Returns

<cString> A character string containing the character or characters required to move the screen cursor or print head to the start of a new line.

Description

Returns a character string containing the character or characters required to move the screen cursor or print head to the start of a new line for the operating system that the program is running on (or thinks it is running on, if an OS emulator is being used).

Under HB_OS_UNIX operating system the return value is the Line-Feed character (0x0a, CHR(10)); with other operating systems (like DOS) the return value is the Carriage-Return plus Line-Feed characters (0x0d 0x0a, CHR(13)+CHR(10)).

Examples

      // Get the newline character(s) for the current OS.
      // Get the newline character(s) for the current OS.
      STATIC s_cNewLine
      ...
      s_cNewLine := hb_eol()
      ...
      OutStd( "Hello World!" + s_cNewLine )

Tests

      ? ValType( hb_eol() ) == "C"
      ? Len( hb_eol() ) == 1

Compliance

Harbour

Platforms

All

Files

Library is rtl

Seealso

OS(), OUTSTD(), OUTERR()

C5DG-9 Terminal Drivers

Clipper 5.x – Drivers Guide

Chapter 9

Alternate Terminal Drivers

Clipper supports a driver architecture that allows Clipper- compiled applications to use alternate terminal drivers. This architecture provides support for nonstandard video hardware and ANSI output devices, allowing your applications to run in a wider variety of environments.

The following terminal drivers are supplied as part of the Clipper Development System and are discussed in this chapter:

. The ANSITERM driver provides ANSI terminal support for systems that require it

. The NOVTERM driver causes Clipper applications to execute faster when run on some nondedicated network server software

. The PCBIOS driver provides direct BIOS calls rather than direct screen writes for systems requiring this form of I/O

In This Chapter

This chapter discusses how Alternate Terminal Drivers fit into the overall Clipper architecture as well as how to install and use each of the supplied terminal drivers. The following major topics are discussed:

. The Alternate Terminal Driver Architecture

. The ANSITERM Alternate Terminal Driver

. The NOVTERM Alternate Terminal Driver

. The PCBIOS Alternate Terminal Driver

The Alternate Terminal Driver Architecture

In Clipper, communication with I/O devices is controlled by a multilayered terminal system. At the lowest level is the terminal driver which controls screen and keyboard activity. It consists of a screen and keyboard driver that communicates directly with the I/O device (operating system or hardware). It is the device specific part of the Clipper terminal system.

There is, then, a higher level system that communicates with terminal drivers. This system is known as the General Terminal (GT) system and provides general services that create Clipper screen and keyboard commands and functions. The following figure demonstrates:

                   +—————————————–+

                   | CA-Clipper screen and keyboard commands |
                   |              and functions              |
                   |-----------------------------------------|
                   |        General Terminal (GT.OBJ)        |
                   ------------------------------------------|
                   |             Terminal Driver             |
                   |-----------------------------------------|
                   |          Screen   |   Keyboard          |
                   +-----------------------------------------+

The default terminal driver, designed for IBM PC and 100% compatibles, is supplied as a library file (TERMINAL.LIB) installed into your \CLIPPER5\LIB directory. This driver links into each program automatically if you specify no alternative terminal driver provided that you do not use the /R option when you compile. An alternate terminal driver is supplied as a separate library (.LIB) file that links into an application program in place of the default terminal driver if you specify it on the link line.

All alternate terminal drivers work through the General Terminal layer as supplied in the file GT.OBJ. The Clipper installation program installs this file in the \CLIPPER5\OBJ subdirectory on the drive that you specify, so you need not install the driver manually.

The ANSITERM Alternate Terminal Driver

The ANSITERM terminal driver supports the ANSI screen mode for all screen display from Clipper programs.

This screen mode is installed by specifying ANSI.SYS in the user’s CONFIG.SYS. ANSI.SYS replaces the default DOS CON device driver for video display and keyboard input. Once installed it supports ANSI escape sequences to erase the screen, set the screen mode, and control the cursor in a hardware-independent way. Most modern DOS programs, however, do not use it and write either directly to the video hardware or use BIOS routines for enhanced screen performance.

Use the ANSI screen mode for Clipper programs that run on hardware that does not support either writing to video hardware or BIOS calls for screen display. This is the case when using alternative display hardware to support the blind.

Note: The ANSITERM terminal driver fully supports all screen and keyboard functionality of the default terminal driver. This includes the ability to save and restore screens and support for all keys on the standard 101-key keyboard.

Installing ANSITERM Terminal Files

The ANSITERM terminal driver is supplied as the file ANSITERM.LIB. The Clipper installation program installs this file in the \CLIPPER5\LIB subdirectory on the drive that you specify, so you need not install it manually.

Linking the ANSITERM Terminal Driver

To link the ANSITERM alternate terminal driver into an application program, you must specify both GT.OBJ and ANSITERM.LIB to the linker along with your application object (.OBJ) modules.

1. To link with .RTLink using positional syntax:

C>RTLINK <appObjectList> GT,,, ANSITERM

2. To link with .RTLink using freeformat syntax:

C>RTLINK FI <appObjectList>, GT LIB ANSITERM

3. To link with .RTLink using ANSITERM.PLL and freeformat syntax:

C>RTLINK FI <appObjectList> /PLL:ANSITERM

Note: These link commands assume you have set the LIB, OBJ, and PLL environment variables to the standard locations. They also assume that the Clipper programs were compiled without the /R option.

Important! You cannot link the ANSITERM driver with BASE52.PLL. An application linked with both ANSITERM.LIB and BASE52.PLL may cause the computer to freeze upon execution.

The Runtime Environment

Using ANSITERM.LIB requires that ANSI.SYS be installed on the user’s computer. To accomplish this, include the following statement in the user’s CONFIG.SYS:

DEVICE=ANSI.SYS

Performance Concerns

Because the ANSITERM terminal driver uses buffered screen writes for all screen painting, some operations, especially those that scroll the screen, are slow. These include:

1. All box drawing commands and functions

2. All console commands and functions when scrolling

3. All clear screen commands and functions

4. All restore screen commands and functions

5. Standard out functions (OUTSTD() and OUTERR()) whether the screen is scrolling or not

Note: Overall performance of Clipper programs is slower since the ANSITERM terminal driver must spend more time polling for user events than the standard Clipper terminal driver.

Screen Output from C and Assembly Language

The ANSITERM terminal driver overwrites all output from C and Assembly Language when it refreshes the screen from the screen buffer. As a consequence, you should perform all screen output from Clipper.

The ANSITERM terminal driver also virtualizes the cursor. This means that BIOS functions that report the location of the hardware cursor will not always return the correct value. To obtain the cursor position, use Clipper’s ROW() and COL() functions instead.

Other Incompatibilities

1. ISCOLOR() always returns false (.F.).

2. When you load DBU, the default color mode is monochrome unless you specify DBU with the /C command line option.

3. The first time you invoke the Debugger, the default color mode is also monochrome unless you set the Options:Mono display off.

4. When an application linked with the ANSITERM terminal driver terminates, the last color set in the application becomes the DOS color. This happens since colors set with ANSITERM are global to DOS and Clipper cannot query DOS for the current screen colors as the application loads.

5. Nondisplaying ASCII characters are presented as a space by the ANSITERM terminal driver. These include BELL (CHR(7)), BS (CHR(8)), TAB (CHR(9)), LF (CHR(10)), CR (CHR(13)), and ESC (CHR(27)).

The NOVTERM Alternate Terminal Driver

The NOVTERM terminal driver is a special-purpose driver that circumvents an incompatibility between some nondedicated network server software and Clipper. This incompatibility causes printers connected to the server to slow to an unusable rate.

Clipper applications and nondedicated servers compete for resources. Clipper applications make use of the time between keystrokes to perform various system tasks. This greatly improves the application’s overall performance by limiting its idle time. Certain nondedicated servers only attempt to print within an application’s idle time. Since a Clipper application is seldom idle, this greatly slows printing.

Important! The NOVTERM terminal driver corrects the incompatibility by preventing the Clipper application from using idle time. Because this can severely hamper performance, you should only use the NOVTERM terminal driver when necessary, and then you should link it only into those applications that are physically running the nondedicated server.

Note: The NOVTERM terminal driver fully supports all screen and keyboard functionality of the default terminal driver. This includes the ability to save and restore screens and support for all keys on the standard 101-key keyboard.

Installing NOVTERM Terminal Files

The NOVTERM terminal driver is supplied as the file NOVTERM.LIB. The Clipper installation program installs the driver file in the \CLIPPER5\LIB subdirectory on the drive that you specify, so you need not install it manually.

Linking the NOVTERM Terminal Driver

To link the NOVTERM alternate terminal driver into an application, you must specify both GT.OBJ and NOVTERM.LIB to the linker with your application object (.OBJ) modules.

1. To link with .RTLink using positional syntax:

C>RTLINK <appObjectList> GT,,, NOVTERM

2. To link with .RTLink using freeformat syntax:

C>RTLINK FI <appObjectList>, GT LIB NOVTERM

3. To link with .RTLink using NOVTERM.PLL and freeformat syntax:

C>RTLINK FI <appObjectList> /PLL:NOVTERM

Note: These link commands assume you have set the LIB, OBJ, and PLL environment variables to the standard locations. They also assume that the Clipper programs were compiled without the /R option.

Important! You cannot link the NOVTERM driver with BASE52.PLL. An application linked with both NOVTERM.LIB and BASE52.PLL may cause the computer to freeze upon execution.

Performance Concerns

Overall performance of Clipper programs is slower since the NOVTERM terminal driver must spend more time polling for user events than the standard Clipper terminal driver and since the program will not use its idle time for other tasks.

Screen Output from C and Assembly Language

The NOVTERM terminal driver overwrites all output from C and Assembly Language when it refreshes the screen from the screen buffer. Therefore, you should perform all screen output from Clipper.

The NOVTERM terminal driver also virtualizes the cursor. This means that BIOS functions that report the location of the hardware cursor will not always return the correct value. To obtain the cursor position, use Clipper’s ROW() and COL() functions.

The PCBIOS Alternate Terminal Driver

The PCBIOS terminal driver uses BIOS calls instead of direct screen writes. It is designedd for applications that trap BIOS calls to redirect output over telecommunication lines or to convert output to a form compatible with two-byte character sets.

Note: The PCBIOS terminal driver fully supports all screen and keyboard functionality of the default terminal driver. This includes the ability to save and restore screens and support for all keys on the standard 101-key keyboard.

Installing PCBIOS Terminal Files

The PCBIOS terminal driver is supplied as the file, PCBIOS.LIB. The Clipper installation program installs the driver file in the \CLIPPER5\LIB subdirectory on the drive that you specify, so you need not install it manually.

Linking the PCBIOS Terminal Driver

To link the PCBIOS alternate terminal driver into an application program, you must specify both GT.OBJ and PCBIOS.LIB to the linker in addition to your application object (.OBJ) modules.

1. To link with .RTLink using positional syntax:

   C>RTLINK <appObjectList> GT,,, PCBIOS;

2. To link with .RTLink using freeformat syntax:

   C>RTLINK FI <appObjectList>, GT LIB PCBIOS

3. To link with .RTLink using PCBIOS.PLL and freeformat syntax:

   C>RTLINK FI <appObjectList> /PLL:PCBIOS

Note: These link commands assume you have set the LIB, OBJ, and PLL environment variables to the standard locations. They also assume that the Clipper programs were compiled without the /R option.

Important! You cannot link the PCBIOS driver with BASE52.PLL. An application linked with both PCBIOS.LIB and BASE52.PLL may cause the user’s computer to freeze when the user executes it.

Performance Concerns

Because the PCBIOS terminal driver uses buffered screen writes for all screen painting, some operations, especially those that scroll the screen, are slow. These include:

1. All box drawing commands and functions

2. All console commands and functions when scrolling

3. All clear screen commands and functions

4. All restore screen commands and functions

5. Standard out functions (OUTSTD() and OUTERR()) whether the screen is scrolling or not

Screen Output from C and Assembly Language

The PCBIOS terminal driver also overwrites all output from C and Assembly Language when it refreshes the screen from the screen buffer. Therefore, you should perform all screen output from Clipper.

The PCBIOS terminal driver also virtualizes the cursor. This means that BIOS functions that report the location of the hardware cursor do not always return the correct value. To obtain the cursor position, use Clipper’s ROW() and COL() functions.

Summary

This chapter has introduced you to the Alternate Terminal Driver concept, giving you specific information on the architecture used to implement them in Clipper. Each of the alternate terminal drivers supplied with Clipper was discussed, including how to link and use it into your application and the implications of doing so.

C5_OUTERR

 OUTERR()
 Write a list of values to the standard error device
------------------------------------------------------------------------------
 Syntax

     OUTERR(<exp list>) --> NIL

 Arguments

     <exp list> is a list of values to display and can consist of any
     combination of data types including memo.

 Returns

     OUTERR() always returns NIL.

 Description

     OUTERR() is identical to OUTSTD() except that it writes to the standard
     error device rather than the standard output device.  Output sent to the
     standard error device bypasses the Clipper console and output devices
     as well as any DOS redirection.  It is typically used to log error
     messages in a manner that will not interfere with the standard screen or
     printer output.

 Examples

     .  This example displays an error message along with the date and
        time of occurrence to the screen:

        OUTERR("File lock failure", DATE(), TIME())

 Files   Library is CLIPPER.LIB.

See Also: OUTSTD()



C5 Error Handling

C5 Error Handling Commands, Statements and Funtions

Statement :

BEGIN SEQUENCE :

Define a sequence of statements for a BREAK

BEGIN SEQUENCE
    <statements>...
    [BREAK [<exp>]]
    <statements>...
    [RECOVER [USING <idVar>]]
    <statements>...
END [SEQUENCE]

Functions :

ALTD() :

Invoke the Clipper Debugger

ALTD( [ <nAction> ] ) --> NIL

BREAK() :

Branch out of a BEGIN SEQUENCE…END construct

BREAK( <exp> ) --> NIL

DOSERROR() :

Return the DOS error number

DOSERROR( [ <nNewOsCode> ] ) --> nOsCode

ERRORBLOCK() :

Post a code block to execute when a runtime error occurs

ERRORBLOCK( [ <bErrorHandler> ] ) --> bCurrentErrorHandler

ERRORLEVEL() :

Set the Clipper return code

ERRORLEVEL( [ <nNewReturnCode> ] ) --> nCurrentReturnCode

NETERR() :

Determine if a network command has failed

NETERR( [ <lNewError> ] ) --> lError

OUTERR() :

Write a list of values to the standard error device

OUTERR( <exp list> ) --> NIL

PROCLINE() :

Return the source line number of the current or previous activation

PROCLINE( [ <nActivation> ] ) --> nSourceLine

PROCNAME() :

Return the name of the current or previous procedure or user-defined function

PROCNAME( [ <nActivation> ] ) --> cProcedureName

Error Class :

Provides objects containing information about runtime errors.

Description :

An Error object is a simple object that contains information pertaining to a runtime error. Error objects have no methods, only exported instance variables. When a runtime error occurs, CA-Clipper creates a new Error object and passes it as an argument to the error handler block specified with the ERRORBLOCK() function. Within the error handler, the Error object can then be queried to determine the nature of the error condition.

Error objects can also be returned to the RECOVER statement of a BEGIN SEQUENCE construct with a BREAK statement. Here, the error object can be queried for local error handling. For more detailed information and examples refer to the Error Handling Strategies chapter in the Programming and Utilities guide.

Class Function :

ErrorNew() :

Returns a new Error object.

ErrorNew() --> objError

Exported Instance Variables :

args (Assignable) :

An array of function or operator arguments.

Contains an array of the arguments supplied to an operator or function when an argument error occurs. For other types of errors, Error:args contains a NIL value.

canDefault (Assignable) :

Indicates whether or not default recovery is available.

Contains a logical value indicating whether the subsystem can perform default error recovery for the error condition. A value of true (.T.) indicates that default recovery is available. Availability of default handling and the actual default recovery strategy depends on the subsystem and the error condition. The minimum action is simply to ignore the error condition.

Default recovery is requested by returning false (.F.) from the error block invoked to handle the error. Note that Error:canDefault is never true (.T.) if Error:canSubstitute is true (.T.).

canRetry (Assignable) :

Indicates whether or not a retry is possible after an error.

Contains a logical value indicating whether the subsystem can retry the operation that caused the error condition. A value of true (.T.) indicates that a retry is possible. Retry may or may not be available, depending on the subsystem and the error condition.

Retry is requested by returning true (.T.) from the error block invoked to handle the error. Note that Error:canRetry never contains true (.T.) if Error:canSubstitute contains true (.T.).

canSubstitute (Assignable) :

Indicates if a new result can be substituted after an error

Contains a logical value indicating whether a new result can be substituted for the operation that produced the error condition. Argument errors and certain other simple errors allow the error handler to substitute a new result value for the failed operation. A value of true (.T.) means that substitution is possible.

The substitution is performed by returning the new result value from the code block invoked to handle the error. Note that Error:canSubstitute is never true (.T.) if either Error:canDefault or Error:canRetry is true (.T.).

cargo (Assignable) :

User-definable variable.

Contains a value of any data type unused by the Error system. It is provided as a user-definable slot, allowing arbitrary information to be attached to an Error object and retrieved later.

description (Assignable) :

Character description of the error condition.

Contains a character string that describes the error condition. A zero-length string indicates that the subsystem does not provide a printable description for the error. If Error:genCode is not zero, a printable description is always available.

filename (Assignable) :

Name of the file associated with the error

Contains a character value representing the name originally used to open the file associated with the error condition. A zero-length string indicates either that the error condition is not associated with a particular file or that the subsystem does not retain filename information.

genCode (Assignable) :

Error code number.

Contains an integer numeric value representing a CA-Clipper generic error code. Generic error codes allow default handling of similar errors from different subsystems. A value of zero indicates that the error condition is specific to the subsystem and does not correspond to any of the generic error codes. The header file, Error.ch, provides a set of manifest constants for generic error codes.

operation (Assignable) :

Character description of the failed operation.

Contains a character string that describes the operation being attempted when the error occurred. For operators and functions, Error:operation contains the name of the operator or function. For undefined variables or functions, it contains the name of the variable or function. A zero-length string indicates that the subsystem does not provide a printable description of the operation.

osCode (Assignable) :

Operating system error code number

Contains an integer numeric value representing the operating system error code associated with the error condition. A value of zero indicates that the error condition was not caused by an error from the operating system. When Error:osCode is set to a value other than zero DOSERROR() is updated with the same value.

Error:osCode properly reflects the DOS extended error code for file errors. This allows proper distinction between errors which result from sharing violations (e.g., opening EXCLUSIVE when another process has already opened the file) and access violations (e.g., opening read/write when the file is marked read-only).

For a list of DOS error codes please look at here 

severity (Assignable) :

Indicates error severity

Contains a numeric value indicating the severity of the error condition. Four standard values are defined in Error.ch:

Error:severity Values
------------------------------------------------------------
Error.ch        Meaning
------------------------------------------------------------
ES_WHOCARES     The condition does not represent a failure;
                the error is informational.
ES_WARNING      The condition does not prevent further
                operations, but may result in a more serious 
                error later. 
ES_ERROR        The condition prevents further operations without 
                corrective action of some kind. 
ES_CATASTROPHIC The condition requires immediate termination 
                of the application.
------------------------------------------------------------

Note that the Clipper runtime support code only generates errors with severities of ES_WARNING or ES_ERROR

subCode (Assignable) :

Subsystem-specific error code number.

Contains an integer numeric value representing a subsystem-specific error code. A value of zero indicates that the subsystem does not assign any particular number to the error condition.

subSystem (Assignable) :

Character description of the subsystem generating the error.

Contains a character string representing the name of the subsystem generating the error. For errors with basic CA-Clipper operators and functions, the subsystem name “BASE” is given. For errors generated by a database driver, Error:subSystem contains the name of the database driver

tries (Assignable) :

Number of times the failed operation has been attempted.

Contains an integer numeric value representing the number of times the failed operation has been attempted. When Error:canRetry is true (.T.), Error:tries can be used to limit the number of retry attempts. A value of zero indicates that the subsystem does not track the number of times the operation has been tried.

Examples :

. This example demonstrates how a file open operation might be handled in an error handler replicating the default CA-Clipper behavior. When, for example, an attempt to open a database file with a USE command fails, control returns to the statement following the offending command:

#include "Error.ch"
#command RETRY => RETURN (.T.) // Retry operation
#command RESUME => RETURN (.F.) // Default recovery
//
FUNCTION MyError( objError )
   //
   // Handle file open error
   IF objError:genCode == EG_OPEN .AND.;
      objError:canDefault .AND.;
      NETERR()
   //
      RESUME
   ENDIF
  .
  . <other error statements>
  .
RETURN NIL

. This example retries an operation within an error handler a specified number of times:

 #include "Error.ch"
 #command RETRY => RETURN (.T.) // Retry operation
 #command RESUME => RETURN (.F.) // Default recovery
 //
FUNCTION MyError( objError )

 // Handle printer not ready error
 IF objError:genCode == EG_PRINT .AND.;
    objError:canRetry .AND.;
    objError:tries < 25

    RETRY
 ENDIF
 .
 . <other error statements>
 .
 RETURN NIL

. This code fragment returns an error object from an error handler to the RECOVER statement for further processing:

LOCAL objLocal, bLastHandler
// Save current and set new error handler
bLastHandler := ERRORBLOCK({ |objErr| ;
MyHandler(objErr, .T.)})
BEGIN SEQUENCE
   .
   . <operation that might fail>
   .
   RECOVER USING objLocal
   .
   . <send messages to objLocal and handle the error>
   .
END
// Restore previous error handler
ERRORBLOCK( bLastHandler )
FUNCTION MyHandler( objError, lLocalHandler )

    // Handle locally returning the error object
    IF lLocalHandler
       BREAK objError
    ENDIF
    .
    . <other statements to handle the error>
    .
RETURN NIL

Files: Header file is Error.ch, default error handler is in Errorsys.prg.

C5 UI Commands & Functions

C5 User Interface Commands and Functions

Global Settings :

SET CENTURY :

Modify the date format to include or omit century digits

SET CENTURY on | OFF | <xlToggle>

SET COLOR* :

Define screen colors

SET COLOR | COLOUR TO [[<standard>]
    [,<enhanced>] [,<border>] [,<background>]
    [,<unselected>]] | (<cColorString>)

SET CONFIRM :

Toggle required exit key to terminate GETs

SET CONFIRM on | OFF | <xlToggle>

SET CONSOLE :

Toggle console display to the screen

SET CONSOLE ON | off | <xlToggle>

SET CURSOR :

Toggle the screen cursor on or off

SET CURSOR ON | off | <xlToggle>

SET DATE :

Set the date format for input and display

SET DATE FORMAT [TO] <cDateFormat>
SET DATE [TO] AMERICAN | ansi | british | french
    | german | italian | japan | usa

SET DECIMALS :

Set the number of decimal places displayed

SET DECIMALS TO [<nDecimals>]

SET DELIMITERS :

Toggle or define GET delimiters

SET DELIMITERS on | OFF | <xlToggle>
SET DELIMITERS TO [<cDelimiters> | DEFAULT]

SET DEVICE :

Direct @…SAYs to the screen or printer

SET DEVICE TO SCREEN | printer

SET EPOCH :

Control the interpretation of dates with no century digits

SET EPOCH TO <nYear>

SET FIXED :

Toggle fixing of the number of decimal digits displayed

SET FIXED on | OFF | <xlToggle>

SETBLINK() :

Toggle asterisk (*) interpretation in SET COLOR

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

SETCOLOR() :

Return the current colors and optionally set new colors

SETCOLOR([<cColorString>]) --> cColorString

SETCURSOR() :

Set the cursor shape

SETCURSOR([<nCursorShape>]) --> nCurrentSetting

SETMODE() :

Change display mode to specified number of rows and columns

SETMODE(<nRows>, <nCols>) --> lSuccess

SETPOS() :

Move the cursor to a new position

SETPOS(<nRow>, <nCol>) --> NIL

User Input :

CLEAR TYPEAHEAD :

Empty the keyboard buffer

CLEAR TYPEAHEAD

INKEY() :

Extract a character from the keyboard buffer

 
INKEY( [ <nSeconds> ] ) --> nInkeyCode

KEYBOARD :

Stuff a string into the keyboard buffer

KEYBOARD <cString>

LASTKEY() :

Return the INKEY() value of the last key in the buffer

LASTKEY() --> nInkeyCode

NEXTKEY() :

Read the pending key in the keyboard buffer

NEXTKEY() --> nInkeyCode

SET TYPEAHEAD :

Set the size of the keyboard buffer

SET TYPEAHEAD TO <nKeyboardSize>

Basic :

?/?? :

Display one or more values to the console

? | ?? [<exp list>]

@…BOX :

Draw a box on the screen

@ <nTop>, <nLeft>, <nBottom>, <nRight>
  BOX <cBoxString> [COLOR <cColorString>]

@…CLEAR :

Clear a rectangular region of the screen

@ <nTop>, <nLeft> [CLEAR
  [TO <nBottom>, <nRight>]]

@…SAY :

Display data at a specified screen or printer row and column

@ <nRow>, <nCol>
    [SAY <exp>
    [PICTURE <cSayPicture>]
    [COLOR <cColorString>]]
    GET <idVar>
    [PICTURE <cGetPicture>]
    [COLOR <cColorString>]
    [WHEN <lPreExpression>]
    [RANGE* <dnLower>, <dnUpper>] |
    [VALID <lPostExpression>]

@…TO :

Draw a single or double line box

@ <nTop>, <nLeft>
    TO <nBottom>, <nRight> [DOUBLE] [COLOR
    <cColorString>]

ACCEPT :

Place keyboard input into a memory variable

ACCEPT [<expPrompt>] TO <idVar>

INPUT :

Enter the result of an expression into a variable

INPUT [<expPrompt>] TO <idVar>

 

ALERT() :

Display a simple modal dialog box

ALERT( <cMessage>, [<aOptions>] ) --> nChoice

CLEAR SCREEN :

Clear the screen and home the cursor

CLEAR [SCREEN] | CLS

COL() :

Return the screen cursor column position

COL() --> nCol

COLORSELECT()

                Activate attribute in current color settings

   COLORSELECT(<nColorIndex>) --> NIL

DEVOUT() :

Write a value to the current device

DEVOUT(<exp>, [<cColorString>]) --> NIL

DEVOUTPICT() :

Write a value to the current device using a picture clause

DEVOUTPICT(<exp>, <cPicture>, [<cColorString>]) --> NIL

           DEVPOS() :

Move the cursor or printhead to a new position depending on the

current device

        DEVPOS(<nRow>, <nCol>) --> NIL

DISPBEGIN() :

Begin buffering screen output

DISPBEGIN() --> NIL

DISPBOX() :

Display a box on the screen

DISPBOX(<nTop>, <nLeft>, <nBottom>, <nRight>,
    [<cnBoxString>], [<cColorString>]) --> NIL

DISPCOUNT() :

Return the number of pending DISPEND() requests

DISPCOUNT() --> nDispCount

DISPEND() :

Display buffered screen updates

DISPEND() --> NIL

DISPOUT() :

Write a value to the display

DISPOUT(<exp>, [<cColorString>]) --> NIL

OUTERR() :

Write a list of values to the standard error device

OUTERR(<exp list>) --> NIL

OUTSTD() :

Write a list of values to the standard output device

OUTSTD(<exp list>) --> NIL

QOUT() :

Display a list of expressions to the console

QOUT([<exp list>]) --> NIL
QQOUT([<exp list>]) --> NIL

RESTORE SCREEN* :

Display a saved screen

RESTORE SCREEN [FROM <cScreen>]

RESTSCREEN() :

Display a saved screen region to a specified location

RESTSCREEN([<nTop>], [<nLeft>],
    [<nBottom>], [<nRight>], <cScreen>) --> NIL

ROW() :

Return the screen row position of the cursor

ROW() --> nRow

SAVE SCREEN* :

Save current screen to a buffer or variable

SAVE SCREEN [TO <idVar>]

SAVESCREEN() :

Save a screen region for later display

SAVESCREEN([<nTop>], [<nLeft>],
    [<nBottom>], [<nRight>]) --> cScreen

SCROLL() :

Scroll a screen region up or down

SCROLL([<nTop>], [<nLeft>],
     [<nBottom>], [<nRight>], [<nVert>] [<nHoriz>])
 --> NIL

TYPE :

Display or print the contents of a text file

TYPE <xcFile> [TO PRINTER] [TO FILE <xcOutFile>]

Advanced :

ACHOICE() :

Execute a pop-up menu

ACHOICE(<nTop>, <nLeft>, <nBottom>, <nRight>,
    <acMenuItems>,
    [<alSelectableItems> | <lSelectableItems>],
    [<cUserFunction>],
    [<nInitialItem>],
    [<nWindowRow>]) --> nPosition

BROWSE()* :

Browse records within a window

BROWSE([<nTop>], [<nLeft>],
    [<nBottom>], [<nRight>]) --> lSuccess

DBEDIT() :

Browse records in a table format

DBEDIT( [<nTop>], [<nLeft>],
    [<nBottom>], <nRight>],
    [<acColumns>],
    [<cUserFunction>],
    [<acColumnSayPictures> | <cColumnSayPicture>],
    [<acColumnHeaders> | <cColumnHeader>],
    [<acHeadingSeparators> | <cHeadingSeparator>],
    [<acColumnSeparators> | <cColumnSeparator>],
    [<acFootingSeparators> | <cFootingSeparator>],
    [<acColumnFootings> | <cColumnFooting>]) --> NIL

DISPLAY :

Display records to the console

DISPLAY <exp list>
    [TO PRINTER] [TO FILE <xcFile>]
    [<scope>] [WHILE <lCondition>]
    [FOR <lCondition>] [OFF]

LIST :

List records to the console

LIST <exp list>
    [TO PRINTER] [TO FILE <xcFile>]
    [<scope>] [WHILE <lCondition>]
    [FOR <lCondition>] [OFF]

LABEL FORM :

Display labels to the console

LABEL FORM <xcLabel>
    [TO PRINTER] [TO FILE <xcFile>] [NOCONSOLE]
    [<scope>] [WHILE <lCondition>] [FOR <lCondition>]
    [SAMPLE]

REPORT FORM :

Display a report to the console

REPORT FORM <xcReport>
    [TO PRINTER] [TO FILE <xcFile>] [NOCONSOLE]
    [<scope>] [WHILE <lCondition>] [FOR <lCondition>]
    [PLAIN | HEADING <cHeading>] [NOEJECT] [SUMMARY]

TEXT :

Display a literal block of text

TEXT [TO PRINTER] [TO FILE <xcFile>]
    <text>...
ENDTEXT

GET System :

Standard :

@…GET :

Create a new Get object and display it on the screen

@ <nRow>, <nCol>
    [SAY <exp>
    [PICTURE <cSayPicture>]
    [COLOR <cColorString>]]
    GET <idVar>
    [PICTURE <cGetPicture>]
    [COLOR <cColorString>]
    [WHEN <lPreExpression>]
    [RANGE* <dnLower>, <dnUpper>] |
    [VALID <lPostExpression>]

CLEAR GETS :

Release Get objects from the current GetList array

CLEAR GETS

READ :

Activate full-screen editing mode using Get objects

READ [SAVE]

READEXIT() :

Toggle Uparrow and Downarrow as READ exit keys

READEXIT([<lToggle>]) --> lCurrentState

READINSERT() :

Toggle the current insert mode for READ and MEMOEDIT()

READINSERT([<lToggle>]) --> lCurrentMode

READKEY()* :

Determine what key was used to terminate a READ

READKEY() --> nReadkeyCode

READMODAL() :

Activate a full-screen editing mode for a GetList

READMODAL(<aGetList>) --> NIL

READVAR() :

Return the current GET/MENU variable name

READVAR() --> cVarName

SET ESCAPE :

Toggle Esc as a READ exit key

SET ESCAPE ON | off | <xlToggle>

SET FORMAT :

Activate a format when READ is executed

SET FORMAT TO [<idProcedure>[.<ext>]]

SET INTENSITY :

Toggle enhanced display of GETs and PROMPTs

SET INTENSITY ON | off | <xlToggle>

SET SCOREBOARD :

Toggle the message display from READ or MEMOEDIT()

SET SCOREBOARD ON | off | <xlToggle>

UPDATED() :

Determine if any GET changed during a READ

UPDATED() --> lChange

Getsys.prg Functions :

GETACTIVE() :

Return the currently active Get object

GETACTIVE() --> objGet

GETAPPLYKEY() :

Apply a key to a Get object from within a Get reader

GETAPPLYKEY(<oGet>, <nKey>) --> NIL

GETDOSETKEY() :

Process SET KEY during Get editing

GETDOSETKEY(<oGet>) --> NIL

GETPOSTVALIDATE() :

Postvalidate the current Get object

GETPOSTVALIDATE(<oGet>) --> lSuccess

GETPREVALIDATE() :

Prevalidate a Get object

GETPREVALIDATE(<oGet>) --> lSuccess

GETREADER() :

Execute standard READ behavior for a Get object

GETREADER(<oGet>) --> NIL

READFORMAT() :

Return, and optionally set, the format file code block

READFORMAT([<bFormat>]) --> bCurrentFormat

READKILL() :

Return, and optionally set, the READ terminate flag

READKILL([<lKillRead>]) --> lCurrentSetting

READUPDATED() :

Return, and optionally set, whether a Get changed

READUPDATED([<lChanged>]) --> lCurrentSetting

GET Class :

Class Function :

GetNew() : Create a new Get object

Exported Instance Variables :

badDate : Indicates if the editing buffer contains an invalid date
block : Code block to associate Get with a variable
buffer : Character value that defines the editing buffer
cargo : User-definable variable
changed : Indicates whether the Get:buffer has changed
clear : Indicates whether the editing buffer should be cleared
col : Get column number
colorSpec : Display attributes string
decPos : Decimal point position within the editing buffer
exitState : Means by which the user exited the Get
hasFocus : Indicates whether or not the Get object has input focus
minus : Indicates whether or not a minus sign has been entered
name : Get variable name
original : Character string containing the original value of the Get
picture : PICTURE string
pos : Current cursor position within the editing buffer
postBlock : Code block to validate a newly entered value
preBlock : Code block to decide if editing is permitted
reader : Contains a block to affect READ behavior on a Get object
rejected : Indicates if last insert/overStrike character was rejected
row : Get row number
subscript : Information about array Get objects .
type : Get variable data type
typeOut : Indicates attempt to move the cursor out of editing buffer

Exported Methods :

State Change Methods :

assign() : Assigns the editing buffer contents to the Get variable
colorDisp() : Changes a Get object’s color and then redisplay it
display() : Displays the Get on the screen .
killFocus() : Takes input focus away from the Get object
reset() : Resets the internal state information of the Get
setFocus() : Gives input focus to the Get object
undo() : Sets the Get variable back to Get:original
unTransform() : Converts character value to its original data type
updateBuffer() : Updates the editing buffer and redisplays the Get
varGet() : Returns the current value of the Get variable
varPut() : Sets the Get variable to the passed value

Cursor Movement Methods :

end() : Moves the cursor to the rightmost position
home() : Moves the cursor to the leftmost position
left() : Moves the cursor left one character
right() : Moves the cursor right one character
toDecPos() : Moves the cursor to the immediate right of Get:decPos
wordLeft() : Moves the cursor left one word
wordRight() : Moves the cursor right one word

Editing Methods :

backspace() : Moves the cursor to the left and deletes one character
delete() : Deletes the character under the cursor
delEnd() : Deletes from current cursor position to the end of the Get
delLeft() : Deletes the character to the left of the cursor
delRight() : Deletes the character to the right of the cursor
delWordLeft() : Deletes the word to the left of the cursor
delWordRight() : Deletes the word to the right of the cursor

Text Entry Methods :

insert() : Inserts characters into the editing buffer
overStrike() : Overwrites characters in the editing buffer

Menu System :

@…PROMPT :

Paint a menu item and define a message

@ <nRow>, <nCol> PROMPT <cMenuItem>
     [MESSAGE <cExpression>]

MENU TO :

Execute a lightbar menu for defined PROMPTs

     MENU TO <idVar>

          MENUMODAL :

Activate a top bar menu

         MENUMODAL(<oTopBar>, <nSelection>, <nMsgRow>,
             <nMsgLeft>, <nMsgRight>, <cMsgColor>) --> MenuID

SET MESSAGE :

Set the @…PROMPT message line row

SET MESSAGE TO [<nRow> [CENTER | CENTRE]]

SET INTENSITY :

Toggle enhanced display of GETs and PROMPTs

SET INTENSITY ON | off | <xlToggle>

SET WRAP :

Toggle wrapping of the highlights in MENUs

SET WRAP on | OFF | <xlToggle>

Browse Classes :

TBrowse :

Provides objects for browsing table-oriented data.

Description :

A TBrowse object is a general purpose browsing mechanism for table-oriented data. TBrowse objects provide a sophisticated architecture for acquiring, formatting, and displaying data. Data retrieval and file positioning are performed via user-supplied code blocks, allowing a high degree of flexibility and interaction between the browsing mechanism and the underlying data source. The format of individual data items can be precisely controlled via the TBColumn data retrieval code blocks; overall display formatting and attributes can be controlled by sending appropriate messages to the TBrowse object.

A TBrowse object relies on one or more TBColumn objects. A TBColumn object contains the information necessary to define a single column of the browse table (see TBColumn class in this chapter).

During operation, a TBrowse object retrieves data by evaluating code blocks. The data is organized into rows and columns and displayed within a specified rectangular region of the screen. The TBrowse object maintains an internal browse cursor. The data item on which the browse cursor rests is displayed in a highlighted color. (The actual screen cursor is also positioned to the first character of this data item.)

Initially, the browse cursor is placed on the data item at the top left of the browse display. Messages can then be sent to the TBrowse object to navigate the displayed data, causing the browse cursor to move. These messages are normally sent in response to user keystrokes.

New data is automatically retrieved as required by navigation requests. When navigation proceeds past the edge of the visible rectangle, rows or columns beyond that edge are automatically brought into view. When new rows are brought into view, the underlying data source is repositioned by evaluating a code block.

Note: TBrowse objects do not clear the entire window before output during redisplay operations. Part of the window may still be cleared when data from the existing display is scrolled.

Class Functions :

TBrowseNew() :

Create a new TBrowse object

 TBrowseNew(<nTop>, <nLeft>, <nBottom>, <nRight>)
 --> objTBrowse

Returns a new TBrowse object with the specified coordinate settings. The TBrowse object is created with no columns and no code blocks for data positioning. These must be provided before the TBrowse object can be used.

TBrowseDB() :

Create a new TBrowse object for browsing a database file

 TBrowseDB(<nTop>, <nLeft>, <nBottom>, <nRight>)
 --> objTBrowse

Returns a new TBrowse object with the specified coordinate settings and default code blocks for data source positioning within database files. The default code blocks execute the GO TOP, GO BOTTOM, and SKIP operations.

Note that TBrowseDB() creates an object with no column objects. To make the TBrowse object usable, you must add a column for each field to be displayed

Exported Instance Variables:

autoLite : Logical value to control highlighting
cargo : User-definable variable
colCount : Number of browse columns
colorSpec : Color table for the TBrowse display
colPos : Current cursor column position
colSep : Column separator character
footSep : Footing separator character
freeze : Number of columns to freeze
goBottomBlock : Code block executed by TBrowse:goBottom()
goTopBlock : Code block executed by TBrowse:goTop()
headSep : Heading separator character
hitBottom : Indicates the end of available data
hitTop : Indicates the beginning of available data
leftVisible : Indicates position of leftmost unfrozen column in display
nBottom : Bottom row number for the TBrowse display
nLeft : Leftmost column for the TBrowse display
nRight : Rightmost column for the TBrowse display
nTop : Top row number for the TBrowse display
rightVisible : Indicates position of rightmost unfrozen column in display
rowCount : Number of visible data rows in the TBrowse display
rowPos : Current cursor row position
skipBlock : Code block used to reposition data source
stable : Indicates if the TBrowse object is stable

Exported Methods:

Cursor Movement Methods :

down() : Moves the cursor down one row
end() : Moves the cursor to the rightmost visible data column
goBottom() : Repositions the data source to the bottom of file
goTop() : Repositions the data source to the top of file
home() : Moves the cursor to the leftmost visible data column
left() : Moves the cursor left one column
pageDown() : Repositions the data source downward
pageUp() : Repositions the data source upward
panEnd() : Moves the cursor to the rightmost data column
panHome() : Moves the cursor to the leftmost visible data column
panLeft() : Pans left without changing the cursor position
panRight() : Pans right without changing the cursor position
right() : Moves the cursor right one column
up() : Moves the cursor up one row

Miscellaneous Methods :

addColumn() : Adds a TBColumn object to the TBrowse object
colorRect() : Alters the color of a rectangular group of cells
colWidth() : Returns the display width of a particular column
configure() : Reconfigures the internal settings of the TBrowse object
deHilite() : Dehighlights the current cell
delColumn() : Delete a column object from a browse
forceStable() : Performs a full stabilization .
getColumn() : Gets a specific TBColumn object
hilite() : Highlights the current cell
insColumn() : Insert a column object in a browse
invalidate() : Forces redraw during next stabilization
refreshAll() : Causes all data to be refreshed during the next stabilize
refreshCurrent() : Causes the current row to be refreshed on next stabilize
setColumn() : Replaces one TBColumn object with another
stabilize() : Performs incremental stabilization

TBColumn :

Provides the column objects TBrowse objects.

Description :

A TBColumn object is a simple object containing the information needed to fully define one data column of a TBrowse object (see the TBrowse reference in this chapter). TBColumn objects have no methods, only exported instance variables.

Class Function :

TBColumnNew() :

Create a new TBColumn object.

TBColumnNew(<cHeading>, <bBlock>) --> objTBColumn

Exported Instance Variables :

block : Code block to retrieve data for the column
cargo : User-definable variable
colorBlock : Code block that determines color of data items
colSep : Column separator character
defColor : Array of numeric indexes into the color table
footing : Column footing
footSep : Footing separator character
heading : Column heading
headSep : Heading separator character
width : Column display width

Example :

This example is a code fragment that creates a TBrowse object and adds some TBColumn objects to it:

USE Customer NEW
//
// Create a new TBrowse object
objBrowse := TBrowseDB(1, 1, 23, 79)
//
// Create some new TBColumn objects and
// add them to the TBrowse object
objBrowse:addColumn(TBColumnNew( "Customer", ;
                    {|| Customer->Name} ))
objBrowse:addColumn(TBColumnNew( "Address", ;
                    {|| Customer->Address} ))
objBrowse:addColumn(TBColumnNew( "City", ;
                    {|| Customer->City} ))
.
. <statements to actually browse the data>
.
CLOSE Customer

For a simple and working sample look at here.