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Additional Strings Functions and Procedures This UNIT contains some additional string functions which for reasons of their own the wizards at Borland left out of Turbo V4.0. I have found these routines to be quite useful and decided to implement them as a UNIT. When using these routines you will notice that many of them require a parameter in the form of SIZEOF(x). I did this so that the assembly routine which actually performs the function would have the maximum size of the string variable being used and could therefore check for overflow. Only the StringOf function does not require this. I have found the Extract type functions most useful in scanning input parameters. If you do a lot of processing of words they again will prove quite useful and most efficient as in addition to copying the substring they also remove it from the source string. All routines are implemented in assembly code for maximum speed. I have included the assembly source in case you decide you don't like the name of a routine (often the case with myself) or some such thing. If any errors are found please notify me via the BPROGA forum or via EASYPLEX. I would also like to hear of any ideas you may have for additional functions to be included in the future. Happy Programming Jan St Martin ----------------------------------------------------------------------------- ExtractForCount Declaration target_str := ExtractForCount(source_string, sizeof(target_string, start_pos) Operation This FUNCTION will move 'n' characters from the source string into the target string starting from the character in the source string pointed to by start_pos). Once the characters have been moved into the target string they are deleted from the source string. ExtractToChar Declaration target_str := ExtractToChar(source_str, sizeof(target_str), search_char) Operation This FUNCTION will move characters from the source string into the target string UNTIL the a character matching search_char is encountered. When the search_char is matched character movement stops (movement does not include the search_char). The characters that were moved are deleted from the source string. Translate Declaration Translate(str_to_translate, translate_table); Operation This PROCEDURE will translate the string indicated by str_to_translate according to the 256 character translation table specified by the second operand. The translation table is assumed to be 256 bytes in length and must be setup by the caller. For each byte in the str_to_translate, the character is extracted and it's logical value is added to the starting address of the translation table. The table character pointed by that sum is used to replace the original character. PadLeft Declaration PadLeft(string, sizeof(string), new_length, pad_char); Operation This PROCEDURE will insert pad_char into the 1st position of string until the length of string is equal to new_length or the string reaches it's maximum size. PadRight Declaration PadRight(string, sizeof(string), new_length, pad_char); Operation This PROCEDURE will insert pad_char into the LAST position of string until the length of string is equal to new_length or the string reaches it's maximum size. Uppercase Declaration target_str := Uppercase (source_str); Operation This FUNCTION will convert each character within the range of a..z in the source_string into it's corresponding uppercase character and place it into the target_string. StringOf Declaration target_str := StringOf (pad_char, string_len); Operation This FUNCTION will create a string containing string_len occurances of pad_char. The original contents of the string are ignored and the user is assumed to know what he/she is doing as there is no check for excedding the maximum length of the string. Graph unit ARTY4 PAS - Example program for the Graph unit GRLINK PAS - Example program for the Graph unit that shows how to link font and driver files into an .EXE file. DRIVERS PAS - Example unit for use with GRLINK.PAS FONTS PAS - Example unit source for use with GRLINK.PAS GRLINK MAK - Make file for use with GRLINK.PAS MCALC PAS - MicroCalc example program MC?????? PAS - Supporting units for MicroCalc MCMVSMEM ASM - Assembler routine used by MicroCalc MCMVSMEM OBJ - Assembled version of MCMVSMEM.ASM UNPACK COM - Utility to unpack GREXAMPL.ARC GREXAMPL ARC - Binary file that contains revised graphics examples from the programs for GRAPH unit. FILELIST - List of the example programs in GREXAMPL.ARC and the corresponding procedure/function names and manual page numbers. ARC PAS - Arc example program ARCCOORD PAS - GetArcCoords example program ASPECT PAS - GetAspectRatio example program BAR PAS - Bar example program BAR3D PAS - Bar3D example program CIRCLE PAS - Circle example program CLOSEGR PAS - CloseGraph example program CLRDEV PAS - ClearDevice example program CLRVP PAS - ClearViewPort example program DETECT PAS - DetectGraph example program DRPOLY PAS - DrawPoly example program ELLIPSE PAS - Ellipse example program FILLPOLY PAS - FillPoly example program FLOOD PAS - FloodFill example program GETBKCOL PAS - GetBkColor example program GETCOL PAS - GetColor example program GETFILLS PAS - GetFillSettings example program GETGRMD PAS - GetGraphMode example program GETLNS PAS - GetLineSettings example program GETMAXX PAS - GetMaxX example program GETMAXY PAS - GetMaxY example program GETPAL PAS - GetPalette example program GETPIX PAS - GetPixel example program GETTXTS PAS - GetTxtSettings example program GETVS PAS - GetViewSettings example program GETX PAS - GetX example program GETY PAS - GetY example program GRERRMSG PAS - GraphErrorMsg example program GRRES PAS - GraphResult example program IMSIZE PAS - ImageSize example program INITGR PAS - InitGraph example program LINE PAS - Line example program LINEREL PAS - LineRel example program LINETO PAS - LineTo example program MOVEREL PAS - MoveRel example program MOVETO PAS - MoveTo example programs OUTTXT PAS - OutText example program OUTTXTXY PAS - OutTextXY example program PIESLICE PAS - PieSlice example program PUTIM PAS - PutImage example program PUTPIX PAS - PutPixel example program RECT PAS - Rectangle example program RESCRT PAS - RestoreCrtMode example program SETACTPG PAS - SetActivePage example program SETALLP PAS - SetAllPalette example program SETBKCOL PAS - SetBkColor example program SETCOL PAS - SetColor example program SETFLPAT PAS - SetFillPattern example program SETGRMOD PAS - SetGraphMode example program SETLNSTY PAS - SetLineStyle example program SETPAL PAS - SetPalette example program SETTXTJS PAS - SetTextJustify example program SETTXTST PAS - SetTextStyle example program SETVISPG PAS - SetVisualPage example program SETVP PAS - SetViewPort example program TXTHT PAS - TextHeight example program 2. HOW TO GET HELP ------------------ If you need help with Turbo Pascal, please read this file and the Reference Manual. If you still have a question and need technical assistance, help is available from the following sources: 1. Type GO BOR on the CompuServe bulletin board system for instant access to the Borland forums with their libraries of technical information and answers to common questions. In addition, all example programs from the manual are available on CompuServe in machine-readable form. If you are not a member of CompuServe, see the enclosed special offer, and write for full details on how to receive a free IntroPak containing a $15 credit toward your first month's online charges. 2. Check with your local software dealer or users' group. 3. Write to: Borland International Turbo Pascal Technical Support 4585 Scotts Valley Drive Scotts Valley, CA 95066 Please remember to include your serial number or we will be unable to process your letter. 4. If you have an urgent problem that cannot wait, you can call the Borland Technical Support Department at (408) 438-5300. Please have the following information ready before calling: A. Product name and serial number from your original distribution disk. Please have your serial number ready or we will be unable to process your call. B. Computer brand, model, and the brands and model numbers of any additional hardware. C. Operating system and version number (the version number can be determined by typing VER at the DOS prompt). D. Contents of your AUTOEXEC.BAT file. E. Contents of your CONFIG.SYS file. 3. CORRECTIONS/ADDITIONS TO THE MANUAL -------------------------------------- NOTE: Important corrections and additions have been made to the GRAPH unit documentation. For the latest information, refer to GRAPH.DOC on Disk III. The file GREXAMPL.ARC on Disk III is a packed file which contains example programs for each of the procedures and functions in the GRAPH unit. In order to use these files, you must first unpack them with UNPACK.COM. The simplest way to unpack the graphics examples is to type: UNPACK GREXAMPL This will extract all the files from GREXAMPL.ARC and place them into the current directory. For a list of other options, type UNPACK at the Dos prompt and hit <Enter>. P-14 Correction The backward slash (\) in the format command should be a forward slash (/): format b: /s P-19 New Help Language Reference Using Ctrl-F1 More than 150 help screens on Turbo Pascal procedures and functions have been added to the online help system. These help topics include an introduction to each standard unit, a listing of all the constants, types, and variables in each of the standard units, and a brief description of every procedure and function described in the reference chapter of the Owner's Handbook (extensively cross-referenced). You can access these language topics using the help index, and by using the Help lookup editor command (Ctrl-F1). For example, go into the editor and type "DiskFree." Then, move the cursor back to the beginning of the word and press Ctrl-F1. The following help screen will be displayed: function DiskFree(Drive: word) : longint; Returns the number of free bytes of a specified disk drive. Unit name Dos See also DiskSize, GetDir If a keyword is not found in the help system, you are given a help screen that describes how to use Ctrl-F1. Ctrl-F1 is an editor command that can be redefined using TINST (described in Appendix F). The identifiers referenced under "Unit name" and "See also" are also help keywords. This means you can get more help on these items by using the cursor control keys and pressing <Enter>. P-20 Using Alt-F1 for Online Help Some help screens are now combined into groups, and the PgUp and PgDn keys can be used to move around within a help group. In addition, the Alt-F1 hot key now remembers groups of screens that were previously viewed, rather than each individual screen. Type PgUp to travel backward through a help group; type PgDn to go forward. A PgUp or PgDn indicator will be present in the lower right corner of the help window if you are inside a help group; otherwise, the PgUp and PgDn keys have no effect. P-30 The variable ErrorCode in example MYTHIRD.PAS should be changed to type integer. P-31 There is a missing less than character (<) in the second While statement in the example at the top of the page. The example reads while Y1 = Finish do but should read while Y1 <= Finish do or else the statement will never be True (since it was initialized to Start on the preceding line). P-40 Turbo Pascal predefines a long integer constant, MaxLongInt, with a value of 2,147,483,647. P-41 The table at the top of page 41 should look like this: Type Range Significant Size in Digits Bytes ------------------------------------------------------------------- real 2.9 X 10E-39 .. 1.7 X 10E38 11-12 6 single 1.5 X 10E-45 .. 3.4 X 10E38 7-8 4 double 5.0 X 10E-324 .. 1.7 X 10E308 15-16 8 extended 1.9 X 10E-4951 .. 1.1 X 10E4932 19-20 10 comp -2E+63 +1 .. 2E+63 -1 19-20 8 P-63 Interface Section If the procedure (or function) is external, the keyword external may only appear in the IMPLEMENTATION section. P-123 Input and Output In version 3.0, you could call the procedure CLOSE on a file that was already closed with no results. In version 4.0, it produces an I/O error, which you can trap by disabling I/O error checking (via the {$I-} option) and testing the value returned by IOResult. P-125 Compiler Directives and Error-Checking The {$I} include file directive is no longer allowed between a begin/end pair. In addition, an include file directive must always have a space between the "I" and the filename. P-126 Assembly Language Usage Inline/external procedures and functions that used byte value parameters in version 3.0 often took advantage of the fact that the high byte of the word pushed on the stack was initialized to 0. In version 4.0 this initialization is not done so you will need to check inline/external routines to make sure they don't assume that the high byte is 0. P-135 New TPMAP Options In addition to converting a .TPM file to a .MAP file, the TPMAP program now also produces a text file that contains a complete list of all units, include files and .OBJ files used by the Turbo Pascal program. For example, given a file named TEST.PAS: program Test; uses Crt; begin ClrScr; Write('Turbo Pascal'); end. then the commands tpc test /$t+ tpmap test will (1) compile TEST.EXE and produce a TEST.TPM file and (2) generate TEST.MAP and TEST.DEP. Here's a dump of TEST.DEP: program TEST in TEST.PAS; uses Crt; unit Crt in CRT.PAS; Links CRT.OBJ; As you can see, the listing contains the module names (TEST, CRT), the corresponding file names (TEST.PAS and CRT.PAS), and a list of .OBJ files linked in using the {$L} compiler directive (CRT.OBJ). TPMAP will only produce a .MAP file if you use the /M command line option. Similarly, the /D option will only produce a .DEP file. P-148 Under the "Bottom Line" section, the bottom line only changes when you hold down the Alt key. P-148 Inserting Compiler Directives into the Editor A new editor command, Ctrl-F7, expands the integrated environment's compiler directive settings into text and inserts them at the beginning of the current edit file. Try loading a file into the editor and pressing Ctrl-F7. If you haven't changed any of the default switch settings on the Options/Compiler menu, the following text will be inserted at the top of the file in the editor: {$R-,S+,I+,D+,T-,F-,V+,B-,N-,L+ } {$M 16384,0,655360 } These are all the options found on the Options/Compiler and Memory sizes menus. In addition, any conditional defines from the Options/Compiler/Conditional defines menu item would have been inserted as {$DEFINE xxxx } directives. P-153 First Letter Movement with Directory Windows You can now move through the directory box by using first letter selection. Pressing the <B> key, for example, takes you to the first file name starting with "B." Pressing <B> again takes you to the next file name, and so on. If there are no other file names beginning with the letter "B," you will be taken back to the first one. If no file names start with the letter "B," then the cursor will not move. Holding down the <Shift> key and pressing <B> will take you to the first subdirectory that begins with the letter "B." P-158 Disregard the last sentence in the paragraph at the top of the page. Compiler options are discussed in the following section. There is no Chapter C. P-170 Pair braces commands (Editor Commands) Here are the correct commands for Pair braces forward and Pair braces backward: Pair braces forward Ctrl-Q [ Pair braces backward Ctrl-Q ] P-170 New Editor Commands The following commands should be added to the table: Language help Ctrl-F1 Insert compiler directives Ctrl-F7 Refer to the P-19 and P-148 README notes above for details. P-184 Quiet Mode Compiler Option A quiet mode option has been added to the command-line compiler. With the default switches, TPC will display the file name and line number of the program module currently being compiled. Using the quiet option: TPC mystuff /Q will suppress the printing of file names and line numbers during the compilation. Normally, TPC reports elapsed compilation time based on the IBM PC's internal timer. On generic MS-DOS machines using the /Q option, the current file name and line number is only updated when files are opened and closed, and the compiler does not calculate the elapsed time. P-191 Add a paragraph to the description of the /R option for TPC: If you need to pass multiple parameters to a program when using the /R option, enclose ALL of the parameters in double quotes. Note that the first double quote must be the character immediately following the R in the /R option (no spaces in between). You can embed slashes and dashes in your parameter line: tpc mystuff /m /r"file1/a file2/b -2" In this case, three parameters would be passed to program mystuff: file1/a, file2/b and -2. P-192 The /x option in the example command at the bottom of this page should be changed to /r. P-229 Variable Typecasts: High-Word/Low-Word Example The built-in functions Hi and Lo return the high- and low-order bytes of a word or integer variable. To determine the high- and low-order words of a long integer variable, you should use a variable typecast: type WordRec = record { used for typecast } Low, High : word; end; var L : longint; begin L := $10000; { 65536 decimal } Writeln(WordRec(L).Low); { 0 } Writeln(WordRec(L).High); { 1 } end. Similarly, here's an inexpensive (code-wise) alternative to the Seg and Ofs functions: type PtrRec = record { used for typecast } Ofs, Seg : word; end; var P : pointer; begin P := Ptr($1234, $4567); Writeln(PtrRec(P).Ofs); { $4567 } Writeln(PtrRec(P).Seg); { $1234 } end. In this example, using a variable typecast generates less code and is faster than using the standard functions Seg and Ofs. P-278 Units That Use Other Units The uses clause in a program or unit may--but does NOT have to--name all units used directly or indirectly. In the example at the top of the page, the uses statement of program Host can be written in several ways: uses Unit1, Unit2; - The identifiers in the interface sections of both units may be referenced in program Host. uses Unit2; - Only the identifiers in the interface section of Unit2 may be referenced in program Host. In the second example, the compiler will recursively analyze unit dependencies and will correctly determine that Unit2 is dependent on Unit1, and that program Host is dependent on both. Note that none of the identifiers declared in the interface section of Unit1 are available to Host because it does not use Unit1 explicitly. P-280 FileMode Variable The FileMode variable defined by the System unit determines the access code passed DOS when typed and untyped files (not text files) are opened using the Reset procedure. The default FileMode is 2, which allows both reading and writing. Assigning another value to FileMode causes all subsequent Resets to use that mode. The range of valid FileMode values depends on the version of DOS in use. However, for all versions, the following modes are defined: 0 - Read only. 1 - Write only. 2 - Read/Write. DOS versions 3.x define additional modes, which are primarily concerned with file-sharing on networks. For further details on these, please refer to your DOS Programmer's Reference manual. Note: New files created using Rewrite are always opened in Read/Write mode, corresponding to FileMode=2. P-296 System Unit Traps Interrupt 24: SaveInt24 The system unit contains an INT 24 handler for trapping critical errors. When running an .EXE program created by Turbo Pascal, a DOS critical error will be treated like any other I/O error: the program counter and an error number will display and the program will terminate. Disk errors are detectable by using {$I-} and checking IOResult. The original INT 24 vector is saved in a pointer variable in the System unit (SaveInt24). Here's a simple program that re-installs the original vector: program Restore; uses Dos; begin SetIntVec($24, SaveInt24); { restore original vector } ... end. P-298, 355 TextRec Record Here is the TextRec as it is actually declared in the Dos unit: { Textfile record } TextBuf = array[0..127] of char; TextRec = record Handle: word; Mode: word; BufSize: word; Private: word; BufPos: word; BufEnd: word; BufPtr: ^TextBuf; OpenFunc: pointer; InOutFunc: pointer; FlushFunc: pointer; CloseFunc: pointer; UserData: array[1..16] of byte; Name: array[0..79] of char; Buffer: TextBuf; end; P-304, 494, 511 TextMode procedure: LastMode and Font8x8 The Mode parameter is of type word. Here is the actual TextMode declaration from the Crt unit: procedure TextMode(Mode: word); In addition, the Last constant described in the manual is now a word variable in the Crt unit and has been renamed to LastMode. Each time TextMode is called, the current video mode is stored in LastMode. In addition, LastMode is initialized at program startup to the then-active video mode. A new constant is now defined in Crt: const Font8x8 = $100; and the TextMode procedure supports 43-line mode on an EGA and 50-line mode on a VGA. The following call to TextMode: TextMode(CO80 + Font8x8) will reset the display into 43 lines and 80 columns on an EGA, or 50 lines and 80 columns on a VGA with a color monitor. TextMode(Lo(LastMode)) always turns off 43- or 50-line mode and resets the display (although it leaves the video mode unchanged); while TextMode(Lo(LastMode) + Font8x8) will keep the video mode the same, but reset the display into 43 or 50 lines. If your system is in 43- or 50-line mode when you load a Turbo Pascal program, the mode will be preserved by the Crt startup code and the window variable that keeps track of the maximum number of lines on the screen (WindMax) will be initialized correctly. P-308, 322, 465 RestoreCrt procedure Instead of the RestoreCrt procedure, the Crt unit contains a word variable, LastMode, that can be used to restore the video mode detected at program startup. When execution begins, Crt stores the then-active video mode in LastMode. In addition, each time TextMode is used to change video modes, the current mode is stored in LastMode. Here's how to write a "well-behaved" program that will restore the video mode to its original state: program Video; uses Crt; var OrigMode : word; begin OrigMode := LastMode; { remember original mode } ... TextMode(OrigMode); end. Note that TextMode does not support graphics modes, and therefore TextMode(OrigMode) will only restore those modes supported by TextMode. For more information on LastMode and TextMode, refer to the P-304 README notes above. P-337 Use of the 8087 within OBJ Files The use of 8087 instructions from object code linked in from .OBJ files is not detected by Turbo Pascal. If you link with an .OBJ file that uses the math coprocessor, the .OBJ must do its own initialization and error-checking. P-340 The default maximum heap memory size is 640 K-bytes. P-347 MyGetMem To conform with the description in the text, procedure MyGetMem should be renamed to GetMem, and a FreeMem routine should be added. The two procedures should look like this: procedure GetMem(var P : pointer; Size : word); begin System.GetMem(P, (Size + 15) and $FFF0); { 16 byte blocks } end; procedure FreeMem(var P : pointer; Size : word); begin System.FreeMem(P, (Size + 15) and $FFF0); { 16 byte blocks } end; P-358 Calling Conventions and Nested Procedures and Functions A procedure or function is said to be nested when it is declared within another procedure or function. Nested procedures and functions always use the NEAR call model, regardless of the setting of the {$F} compiler switch, since they are only "visible" within a specific procedure or function in the same code segment. When calling a nested procedure or function, the compiler generates a PUSH BP instruction just before the CALL, in effect passing the caller's BP as an additional parameter. Once the called procedure has set up its own BP, the caller's BP is accessible as a word stored at [BP+4]. Using this "link" at [BP+4], the called procedure can access the local variables in the caller's stack frame. If the caller itself is also a nested procedure, it also has a link at [BP+4], and so on. The following example demonstrates how to access local variables from an inline statement in a nested procedure: procedure A; var IntA: Integer; procedure B; var IntB: Integer; procedure C; var IntC: Integer; begin inline( $8B/$46/<IntC/ { MOV AX,IntC[BP] ; AX = IntA } $8B/$5E/$04/ { MOV BX,[BP+4] ; BX = B's stack frame } $36/$8B/$47/<IntB/ { MOV AX,SS:IntB[BX] ; AX = IntB } $8B/$5E/$04/ { MOV BX,[BP+4] ; BX = B's stack frame } $36/$8B/$5F/$04/ { MOV BX,SS:[BX+4] ; BX = C's stack frame } $36/$8B/$47/<IntA); { MOV AX,SS:IntA[BX] ; AX = IntA } end {C}; begin {B} end {B}; begin {A} end {A}; Note: Nested procedures and functions cannot be declared with the external directive. P-367 The comments are backward in the inline example on this page. POP AX comes first, followed by POP DX. function LongMul(X,Y : integer) : longint; inline( $58/ { POP AX ; Pop Y } $5A/ { POP DX ; Pop X } $F7/$EA); { IMUL DX ; DX:AX = X*Y } P-373 Example Unit: Unit AuxInOut The example shown at the bottom of the page is incorrect. The correct example is in a file named AUXINOUT.PAS on Disk II. P-402 Add the following paragraph to the description of the Eoln function: When checking Eoln on standard input that has not been redirected, the following program will wait for a carriage return to be entered before returning from the call to Eoln: begin Writeln(Eoln); { This call to Eoln will cause the program to wait for keyboard input } end. P-415 The Declaration for the GetFAttr procedure is procedure GetFAttr(var f; var Attr : word); P-497 Range-Checking With Val The standard procedure Val, which converts a string's contents to a numeric variable, performs range-checking differently depending on the state of {$R} and the type of the parameter V: Val(s : string; var V; var Code : integer); With range-checking on, {$R+}, an out-of-range value always generates a runtime error. With range-checking off, {$R-}, the values for an out-of-range value vary depending upon the data type of V. If V is a real or longint type, the value of V is undefined and Code returns a non-zero value. For any other numeric type, Code returns a value of zero and V will contain the results of an overflow calculation (assuming the string value is within the long integer range). Therefore, you should pass Val a longint variable and perform range-checking before making an assignment of the returned value: {$R-} Val('65536', LongIntVar, Code) if (Code <> 0) or (LongIntVar < 0) or (LongIntVar > 65535) then ... { error } else WordVar := LongIntVar; In this example, LongIntVar would be set to 65536 and Code would equal 0. Because 65536 is out of range for a word variable, an error would be reported. In addition, Val has been modified to ignore leading spaces. P-417 GetFTime The type was omitted from the 2nd parameter. The correct declaration for GetFTime is procedure GetFTime(var F; var Time: longint); P-448 MsDos procedure The MsDos procedure is incorrectly labeled a function. Here's the actual declaration as it appears in the Dos unit: procedure MsDos(var Regs : Registers); P-493 Crt Color Constants There are 16 foreground color constants: const Black = 0; Blue = 1; Green = 2; Cyan = 3; Red = 4; Magenta = 5; Brown = 6; LightGray = 7; DarkGray = 8; LightBlue = 9; LightGreen = 10; LightCyan = 11; LightRed = 12; LightMagenta = 13; Yellow = 14; White = 15; { Add-in for blinking } Blink = 128; P-499 Window A call to the Window procedure always moves the cursor to (1,1). P-510 Differences from 3.0: MemW, FileSize In version 3.0, MemW returned an integer value. In version 4.0, it returns a value of type word. In 4.0, Filesize of an untyped file will ignore a partial block when the block size is greater than 1. P-523 Standard Procedures and Functions In the list provided, two entries are combined into one: FillChar Frac P-529 Force Far Calls Compiler Directive The {$F} (force far calls) compiler directive has no effect on a nested procedure. The nested procedure always uses the near call model. P-565 New Utility Program: BINOBJ.EXE A utility program BINOBJ.EXE has been added that converts any file to an .OBJ file so it can be linked into a Turbo Pascal program as a "procedure." Refer to BINOBJ.DOC on Disk II for more information on this new utility. P-570 The second paragraph on this page should be replaced with the following: See the description of the ReadKey function on page 461 for a description of how to determine if an extended key (function key or cursor movement key) has been pressed. P-586 Automatic Compaq Detection Override The integrated environment will detect whether you are using a Compaq computer and automatically use its black and white color set. This gives better contrast on the composite monitors that are built-in to the vast majority of Compaq computers. If you are using a Compaq computer and a true color monitor, you can force the integrated environment to use its color tables by running TINST, typing "D" to install the Display mode, and selecting Color. P-619 to 630 New Error Messages COMPILER ERROR MESSAGES: 68 Circular unit reference Two units are not allowed to use each other: unit U1; unit U2; uses U2; uses U1; ... ... In this example, doing a Make on either unit will generate error 68. 132 Critical disk error A critical error occurred during compilation (e.g. drive not ready error). 133 Old map file The .TPM file is older than the corresponding .EXE file. It's an indication that the last time you compiled your program, a .TPM file was not produced. For example, if TEST.TPM is older than TEST.EXE, to find a runtime error you must recompile TEST.PAS with the {$T} compiler directive on. RUNTIME ERROR MESSAGES: Critical Errors Runtime errors fall into four categories: DOS errors (1-99), I/O errors (100-149), critical errors (150-199), fatal errors (200-249). The following critical error messages have been added since the manual was printed: 150 Disk is write-protected 151 Unknown unit 152 Drive not ready 153 Unknown command 154 CRC error in data 155 Bad drive request structure length 156 Disk seek error 157 Unknown media type 158 Sector not found 159 Printer out of paper 160 Device write fault 161 Device read fault 162 Hardware failure Refer to your DOS programmer's reference manual for more information about critical errors.