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New items added 10/11/90 through the date of this file Part 1 REDIM PRESERVE with BC7.1 Instant watch with strings QB 4.50 ------------------------------------------------------------------------- This file contains information about bugs, quirks, and general points of interest to programmers working with compiled BASIC. It is divided into four parts: Part 1 - Description of bugs, quirks, etc. Part 2 - General points of interest Part 3 - Sample programs Part 4 - Video adapters compatible with QB 4.50 If you want to find one of the above quickly, use your text editor to search for the text shown above. i.e., Search for "Part 1 -". As of 12/3/88, all new or changed entries will be marked with the date that the information as added or changed. The date will appear in the entry in the format (yy/mm/dd). As of 2/8/89, all references to problems with QB4.00 and QB4.00a have been removed from this file. It is presumed that all QB programmers have upgraded either to QB4.50 or QB4.00b. If you are still using QB4.00 or 4.00a, call Microsoft at 206-454-2030 and ask for a free upgrade to 4.00b. If you are using BASCOM 6, there is a similar upgrade available to BASCOM 6.00b. This file is maintained by Mark Novisoff of MicroHelp, Inc. Much of the information was contributed by members of MicroHelp's BASIC Users Group, users of the MSSYS forum on Compuserve and users of Mach 2, Stay-Res, The MicroHelp Toolbox and the QB/Pro Professional series. If you have additional information that should be added, please send it to: Mark Novisoff MicroHelp, Inc. 4636 Huntridge Drive Roswell GA 30075 Compuserve ID 73047,3706 in MSSYS (Microsoft Systems Forum) If possible, please include a *small* sample program that will demonstrate the problem and cause it to happen whenever the program is run. ------------------------------------------------------------------------- Part 1 - Description of bugs, quirks, etc. ------------------------------------------------------------------------- Note: QB 4 under "Compilers" refers QB4.00b and 4.50. ` Next to a QB 4 entry indicates that the problem has been fixed in QB 4.50 and/or the accompanying BC program. * Next to an entry indicates that the problem has been fixed in QBX and/or the accompanying BC 7.0 program. @ Next to an entry indicates that the problem has been fixed in QBX/BC7.1. Command/Error Compilers Description -------------- --------------- -------------------------------------------- $INCLUDE All If the last line of your $INLUDE file does not have a carriage return/line feed pair, spurious errors can occur! $INCLUDE QB 4 If you have a DEFINT statement in an include file and you wish to use it within subprograms/ functions in a module, you must $INCLUDE it within each sub/function structure. If you simply include it in the mainline code, the DEFINT statement is not recognized. However, if you have a statement DEFINT in your mainline code (as opposed to $INCLUDE), it will work ok. BLOAD All When running on an XT with SMARTDRV.SYS, you may find that the BLOAD will display only the first two screen lines. If so, removing SMARTDRV.SYS will solve the problem. (89/12/22) BLOAD All In order to BLOAD a file, the file must have been previously BSAVEd so that the 7 byte "header" is present. Although it may be possible to BLOAD files that were not saved with this header, it is dangerous because BASIC presumes that the header is there and will not load the first 7 bytes into memory. (89/03/31) CALL (asm) QB 4* If you pass a static string array as a parameter to a subprogram, and the string array represents FIELDed data (as in a random file), AND you call an assembly subroutine that displays the data, your position in the file can be wiped out! See sample program #22. The fix is to place the string array in a COMMON SHARED statement and remove it from the parameter list. Added (88/12/19). Even if the string array is NOT a FIELDed array, the data can become corrupt. The new solution is to move all CALL or CALLS statements that have string arrays as parameters to the MAIN program and remove them from SUBs. CALL QB 4 If you want to pass a single element from a string array to a subprogram, be sure to put an extra pair of parentheses around the variable name in the parameter list. For example, you may have a problem with: CALL MySub(A,B,C$(3),D) However, the following should work: CALL MySub((A,B,(C$(3)),D) CALL (asm) QB 4+/BC6+ Effective with QB 4, assembly language subroutines must preserve the SI and DI registers and make sure the direction flag is cleared before returning to BASIC. In addition, you must not have a label name after the END statement in your assembler code. CALL INIT QB 2-3 Do not name a precompiled subprogram "INIT". If you do, the compiler will go into never- never land when your user library is loaded. CALL vs GOSUB All If you have many calls to the same asm routine or subprogram, you'll use less memory if you set variables and GOSUB to a routine that performs the CALL instead of having the CALL "in line". CALL is much faster using variables than using "literals". CALLS QB 4* If you are passing string arrays to an assembler subroutine, make sure that $Static is in effect (not $Dynamic) when you dimension your array. If you do not, the data are not pushed onto the stack correctly by BC. This affects the use of MhBasStringSort in Mach 2. CALLS QB 4* When CALLS (note the "S") is used and you compile with "/D" (debug), the segment of of a string element descriptor does not get passed on the stack. In other words, if you have an assembly language subroutine that uses CALLS, you should not compile with "/d". CHAIN QB4/BC6* CHAINing from a small .EXE to a large .EXE can cause unpredictable problems. This has been corrected in QB 4.50. (89/07/29) CHAIN BC6.0x* If you are using extended runtime libraries, there are known problems with CHAIN. This includes problems in COMMON SHARED data. (89/07/29) CHAIN BC6.0x BC7.0 Contrary to the docs, the stack size is *not* preserved across a CHAIN. The workaround is to use the /ST:xxxx switch when LINKing your programs. (89/07/29) CHAIN QB 4, QB 3 & CHAIN and RUN will work correctly in DOS 2.1 BASCOM 6 when you compile with the BRUN library. They will not work correctly on the second CHAIN or run attempt if you compile with the BCOM library (/O). You will get one of the following errors: Out of memory, EXE failure, or Error R6005. (89/04/24) CINT QB 4/QBX If the number you want to convert is exactly halfway between two integers (i.e., .5), the rounding is done incorrectly when the number that would normally be the result is an odd number. See example program #30. (89/01/03) It turns out that this works exactly as Microsoft designed it - for statisticians. If the whole portion of the number is odd, the number is rounded up. If the whole portion is even, the number is rounded down. (89/11/03) CIRCLE QB 4/QBX The start and end angles must be LESS than 2*pi. Previously they could be less than or equal to. CLEAR QB 4/QBX If you use SETMEM to free up memory for use by other routines or modules, the CLEAR statement does not force the compiler to give up that memory. In other words, you must explicitly do a SETMEM(640*1024), or other large number. (Also see RUN.) Added 89/02/08: If you have an assembler routine that has allocated memory from the pool created by SETMEM (Mach 2's huge string arrays, for example), using SETMEM(640*1024) will still not release the memory. That's because the underlying program has may have done its own allocation of memory via DOS. In this case, you must force the assembler routine to free up the memory. In the case of Mach 2's huge string arrays, this is done by telling Mach 2 to release the memory. CLEAR,,Size QB 3,4/QBX If you receive an out of stack space message. The stack size is reset between CHAIN'ing but if you CHAIN back to your original program, be sure to skip the CLEAR instruction. Added 89/02/08: This is very important in QB4 if you have recursive subprograms and/or functions. "Recursive" means that the procedure can be invoked from inside the procedure. COMMON and QB 2-4/QBX All statements that use COMMON or variations COMMON SHARED thereon with CHAIN must use parameter lists that match exactly. Best done with $INCLUDE. COMMON with TYPE QB 4/QBX The TYPE statement must appear before the COMMON statement and must appear in all programs that use it. The COMMON statement must contain "AS". See sample program #1 at the end of this file. Compile to EXE QB 4`* QB issues an unusual LINK command in the form of: LINK Prog+YourLib.Lib; This causes LINK to bring the entire library into your program! The solution is to exit QB, and run BC and LINK yourself. Note also that the LIB environment variable is not used to search for libraries in this context, since the library name is in the object module field. CONST in CALL BC7.1 We've had an unconfirmed report that using the *same* CONST multiple times in a CALL, with a subsequent CHAIN, will cause a hang. For example: CONST One = 1 CALL SomeSub(X%, Y%, One, One, One, One) The workaround is to use literals or variables: CALL SomeSub(X%, Y%, 1, 1, 1, 1) OR A% = 1 CALL SomeSub(X%, Y%, A%, A%, A%, A%) (90/08/24) CONST QB 4* Must be included in all program modules that use the constant. Place in the file at the top, rather than inside SUB's. DATA BC4.00b/6.00b* See READ DATA QB 4/QBX When a DATA statement is encountered inside a SUB...END SUB structure, QB moves it into the "mainline" portion of the code when you are in the environment. DECLARE QB 4/QBX QB4 allows you to use a procedure name as a label. See example program #32. (89/02/10) DEFINT QB 4 See $INCLUDE. DEF FN All These functions cause temporary strings to be held in memory. See example program #36. (89/10/10) DEF FN All Functions are local to the module in which the DEF FN appears. Use QB 4's FUNCTION..END FUNCTION for global functions. Device Unavailable (QB4+) This error has been reported, especially when using a fast machine (such as a 386), even though the device is present. The problem appears to be a matter of timing. The solution is to use error trapping and if "Device Unavailable" occurs, retry the OPEN statement three or more times. (90/01/19) DIM QB 3 See sample program #4. QB3 apparently has a limit of 123 dynamic arrays. DIM QB 4/QBX Any array that is DIMmed inside of a subprogram that does not have the STATIC keyword is a DYNAMIC array. DIM QB 4/QBX In order to take advantage of the /AH switch with TYPE..END TYPE records, the record length must be a power of 2 (4,8,16,32, etc.) DIM QB 4/QBX Static numeric arrays are stored on the "heap" when you are inside the QB environment. BC programs store them in the default DS. DIM (TYPE) QB 4/QBX See sample program #1 for dimensioning arrays of TYPE'd variables. Division All Using integer division "\" when an integer result is desired is much faster than normal division "/". DRAW QB 2-4 Does not respect the boundaries designated by WINDOW. Duplicate Definition QB 4 If you receive an otherwise unjustified "Duplicate definition" error, check to see if your program has variables called F$ or F%. When programs reach an undefined "critical mass" (in terms of size), variables using those names will cause the error. The solution is to find and replace all occurrences of those names with other names. (88/12/03) Added 89/02/08: These variable names can also cause "FUNCTION not defined" errors. ENVIRON QB 2-4/QBX If you attempt to create a new environment variable inside a program, you are likely to get an "out of memory" error, because the amount of environment space available when your program runs is very small. To get around this problem, create a good sized dummy variable in your AUTOEXEC.BAT, then inside your program, eliminate it before attempting to setup new variables. Eliminate the variable by using the semicolon: ENVIRON "DUMMY=;". Error R6005 See CHAIN (QB 4) (89/04/24) EXEC Failure See CHAIN (QB 4) (89/04/24) Expression Too Complex QB 4.50/BC7 QB will generate this error if you try to concatenate more than 19 expressions. BC will do the same, but it may point to the wrong line. Specifically, if the BC4.5 compiler gives you this error, check the line *above* the indicated line. You may even get this error when the offending line has been REMmed. (89/07/29) This problem has been fixed in QBX, but still exists in BC 7.0. Far heap corrupt QB 4 When working in the environment, this error can occur when you are *saving* a file that uses several user-defined types and arrays in COMMON. (89/03/31) /FPA BASCOM 6/7 If you use VAL on a string "E9999" (or a similar string with a leading "E") and you compile with /FPA, you'll get an overflow error. Compiling without /FPA yields a VAL of zero. (89/03/31) /FPA BASCOM 6/7 If you use the /FPA switch (alternate floating point math library) when compiling one or more modules, you must use the same switch in ALL modules in the same program. FIELD QB 4 We've had a report that if you use array elements for FIELD'ing a Btrieve file, and you don't DIM the string array (i.e., you default to 10 elements) that you can get string space corrupt errors. The solution is always to DIM the arrays. File not found All See KILL (Network). FILES QB 3 There is a bug in the QB3-8087 compiler that causes FILES not to work correctly. Fixup Overflow BASCOM 6 If you include the Microsoft mouse object module (MOUSE.OBJ) in an extended runtime library, you will get a fixup overflow error. There are two solutions: Put MOUSE.OBJ in your program instead of the ERL, or use an alternate set of mouse routines, such as those in MicroHelp's QB/Pro Volume 4. (89/03/31) FOR/NEXT QB 4/BC7 If you use an integer for a loop counter, and the top of the loop is 32767 (when STEP is positive) or the bottom of the loop is -32768 (when STEP is negative), you'll get an overflow when inside the QB environment or when compiled with BC using "/d". With BC,if you don't use "/d", the loop does not stop at the top/bottom - it wraps around and executes your loop indefinitely. FRE(-3) BC7 If you are not using overlays, and you attempt to use FRE(-3), you will get a "feature unavailable" error. (90/08/27) FRE(-2) All Fre(-2) is unreliable in all versions of QuickBASIC 2-4. See sample program #26. The BC 7.0 documentation explains this. (89/11/03) FUNCTION QB 4 Provides global functions for all modules in a program. All that is needed is a DECLARE statement in any module that needs to use the function. In addition, this type of function can be recursive. See DEF FN. FUNCTION QB 4/QBX/BC7 Cannot be used in $INCLUDE files. GOTO QB 4` See sample program #17. HEX$ QB 4/QBX/BC7 Be careful when using with non-integer values. For example, the output from the two lines shown is "FFFF8002". E&=&H8002 PRINT HEX$(E&) IF..THEN..ELSE QB 3 More than two nestings for ELSE on a single line will not compile properly. IF..THEN..ELSE QB 4 ` See Sample program #9. INPUT QB 4 ` Using INPUT directly to an array element that should generate a "subscript out of range" error causes a hard crash. LINE INPUT generates the error just fine. Note that this error occurs only inside the environment. See Sample program #10. Instant watch with strings QB 4.50 @ See Sample Program #12. (90/10/19) INSTR BC 4.x See Sample Program #37. (89/10/12) INT QB 4/QBX/BC7 See Sample Program #29. (88/12/19) Internal Error QB 4` More problems with long integers. See sample in BC program #25. KILL (Network) All If you get a "file not found" error when attempting to KILL a file on a network drive, and you know the file exists, the problem is most likely due to the user not having "delete" rights in the network. In this case, the network will issue an "access denied" error, which BASIC will translate to "file not found". LIB.EXE n/a LIB cannot recognize the name of a library if you precede the library name with a path that contains a hyphen "-". For example, if you enter the following, LIB will fail: LIB Test-Dir\MyLib <Enter> LINE All* LINE does not respect the boundaries set with VIEW if you draw a filled box with LINE. See sample program #38. LINK with /PAC See sample program #31. Note that the /PAC switch is supported only by the latest versions of LINK. (89/02/10) LINK All Use the /EXEPACK switch to condense the file. Can be used on any program except programs that are CHAIN'ed to using all compilers except QB 4/BC7. All QB 4/BC7 programs can use this switch. Syntax: LINK /EXE Progname (etc.) LINK QB 4 When building a Quick Library, be sure to specify BQLB4x in the library field. Example: LINK /QU ObjMods,Lib,,BQLB40; This also applies to BQLB41 if using BC6 or QB 4.00b and BQLB45 when using QB4.50. Similarly, with QBX use QBXQLB. LOAD QB 4/QBX/BC7 If you receive an "out of memory" error, try breaking your program into logical pieces (using subprograms). Then use COMMON SHARED for all variables that you need in the entire program. The exact same COMMON SHARED declaration must appear in all the modules in the program that need access to the variables. LOAD QB 4* If you download a QB 4 program in "fast load" format, many modem transfer protocols pad the file out using a number of CHR$(0)'s. This will cause QB 4 to crash when you attempt to load the program. Use DEBUG to view the file, then write the program to disk after changing the CX register to shorten the length of the file so that the trailing CHR$(0)'s are not included. The other solution is to download this type of file using an ARC program that restores the original length of the file. LOCK QB 4 If you LOCK records, then perform a SHELL, then you try to UNLOCK the same records, you may get a "permission denied" error (error 70). (88/12/19) LPRINT QB 4.50* See TAB with REDIM (QB 4.50) ON ERROR QB 4` See "RESUME" for QB 4. ON ERROR QB 2-4 Error handler routines must be located outside SUB...END SUB structures. You can RESUME to a line number/label that is outside SUB...END SUB structures (using /E) or to code inside the sub using plain RESUME or RESUME NEXT (/X). Much better is to $INCLUDE subroutines that perform error trapping instead of having them in subprograms. This allows the use of RESUME line number/ label and avoids the /X. Note - with BASCOM 6 and QB 4.00b, error handling has been improved. See the docs. BC7 has "ON LOCAL ERROR", which is even better. OPEN COM QB 4` If you compile with /S, and use OPEN COM with a literal string, the statement will generate "Device Unavailable". See sample program #18. OPEN All With Novell NetWare, using OPEN on a file that does not exist does not always create the file. Novell has acknowledged the problem but they don't have a solution available as of 12/19/87. A workaround for the problem when using Btrieve is to open the NUL device on the local system instead of the network. For example, OPEN "R",1,"A:NUL". Out of memory QB 4 BASCOM 6 See CHAIN (QB 4) Overflow All BASIC uses integer types for all calculations and processes the right side of the equal sign before the left side. To force BASIC to use a different numeric type, place a type identifier on the right of the equal sign. Example: A=Peek(2)+256!*Peek(3) PAINT QBX/BC7@ PAINT can't handle a CHR$(0). See Sample program #3. (90/02/17) Periods in variable names QB 4* We have found numerous problems using periods in variable names. We believe the problems are somehow associated with TYPE..END TYPE user defined records. Because of these problems, we recommend that you do NOT use periods in variable names. See sample program #28 for one example of this problem. (88/12/03) PRINT TAB(x) and PRINT USING QB 4.50* Don't use PRINT TAB(x) to position the cursor immediately before using PRINT USING. See sample program #5. 90/03/05 PRINT CHR$(128) QB 4.50 If you have a program that contains a PRINT "Ç" and you save it in "fast load" format, BC4.50 will not compile it. The solution is to save your programs in text format. (90/02/20) PRINT QB 4.50* See TAB with REDIM (QB 4.50) PRINT All Try this program in QB: (89/02/10) FOR N = 29 TO 31 PRINT N, CHR$(N) NEXT The number "N" will print just fine, but the characters will not. In order to display these characters, use an assembler subroutine, such as MhScr in Mach 2. PRINT # QB 4 In order to print a blank line using QB 4, use the syntax: PRINT #n, Note the absence of the null string after the comma. We've had an unconfirmed report that if the print buffer is filled, using the null string causes characters to be dropped. PRINT USING QB 4/BC7 With previous compilers, you could place TAB statements, variable names, or most anything else between PRINT and USING. With QB 4, nothing should come between PRINT and USING. PUT 4.00b/BC7 See sample program #21. When using the syntax PUT Filenumber,RecordNumber,Variable you'll get a "bad record length". Added 89/10/07 - see sample program #21 for another solution. READ BC4.00b & 6.00b* RUN does not do an implicit RESTORE. See Sample program #34. (89/07/29) READ QB 4` If you want a REMark on a line that contains DATA statements, be sure to put a colon on the line between the end of your data and the REM or '. REDIM PRESERVE BC7.10 When using near strings, there is a BUG that causes "out of string space" errors. See Sample Program #11. REDIM QB 2.01 In EXE programs (not in the environment), the following logic will cause your FIELDed variables to go haywire: REM $DYNAMIC DIM StringArray$(SomeNumber) FIELD #SomeFile.... ... ERASE StringArray$ REDIM StringArray$(ADifferentNumber) SomeVariable = FRE("") The solution to the problem is to reFIELD the file after a REDIM and a FRE(""). REDIM QB 3 If you have a subprogram that REDIM's arrays, and you get a "string space corrupt" message after calling the subprogram several times, try using ERASE on the array before you do the REDIM. REM $INCLUDE QB 4` See sample program #24. REM $TITLE QB1-4/BC7 When you use the REM $TITLE metacommand, you are limited to 60 chars of title. If the title is longer, you'll get an error message "Metacommand error". Note that QB2.01 does not print an error message, but still shows "1 severe error". RESTORE QB 4/BC6 If you have two object modules with the same name (for example, one compiled from TEST.BAS and one from TEST.SUB), and you use RESTORE, and you get an error (or the wrong data) when you use READ, use the '$MODULE metacommand to give one of the modules a different name as far as LINK is concerned. Example: '$Module: 'TEST2' (90/02/26) RESUME All If you always use RESUME <linenumber> or RESUME <label> you can use the "/e" switch instead of "/x". Makes programs smaller! This is not practical for subprograms, so error trapping is better handled in mainline code. See ON ERROR. Note - BC7's ON LOCAL ERROR takes care of RESUME within modules. RESUME QB 4` If you compile to an EXE from inside the environment, a "/X" is generated by QB even though it's not needed. Be sure to recompile with "/E" outside of the environment if your program doesn't need "/X". RUN BC7.1 If you are using far strings, and your program is "runtime" (using BRT71EFR.LIB), and the program is running on a network, and the program you attempt to RUN is in the same directory as the program trying to perform the RUN (whew!), you may get a message asking you to "input path for runtime module". The workaround is to use /O, or to always RUN programs from alternate directories, or to have copies of the runtime library whereever it might be needed. (90/08/23) RUN QB 4 See CLEAR (QB 4) and CHAIN (QB 4) SADD QB 4 When using SADD-188 for Btrieve, be sure to make this calculation EACH TIME you are going to CALL Btrieve. This is because QB 4 can move the FIELD'ed strings around in memory. SAVE QB 4 If you edit a new program and save it, QB defaults to "fast load" format. The file cannot be handled by a text editor. Fix by using "save as". SCREEN (Page) QB 3 If you have a VGA, your system is in 40 column mode, and you use a video page other than 0, you will find that QB3 stores the pages beginning at an offset that is &H100 (decimal 256) higher than it should. Instead of beginning page 1 at offset 2048, (&H800) it starts at offset 2304 (&H900). SCREEN QB 3 If you have a VGA and run the following program, you'll find that your screen has 28 lines! SCREEN 2 SCREEN 0 PRINT "Hello world" The solution is to use MhDos2 (Mach 2) or CALL INTERRUPT (or one of its variations), with the AH register set to 0 and the AL register set to 3. After that, do another SCREEN 0, and you will have 25 lines. SCREEN All ? When reading characters from the screen using SCREEN (X,Y), if the character on the screen is CHR$(0), 32 (blank space) is returned as the result from this function. Using Mach 2's MHRSCR will overcome this problem. SELECT CASE QB 3 Much less forgiving than QB 4. For example, when using a string, you can't say: CASE CHR$(3) However, you can embed the literal character with an ASCII value of 3 in quotes! SELECT CASE QB 4` If you set a breakpoint (using F9) on a CASE statement, the logic of the SELECT CASE... END SELECT fails. See sample program #19. QB 4.50 tells you that you cannot set a breakpoint on a CASE or END SELECT statement. Some fix!!! SELECT CASE QB 4/QBX You cannot have a line number or label between the SELECT CASE and the first CASE. SHARED QB 4 See sample program #23. SOUND QB 3/87 Generates error 6 in all forms when the emulator is used on non-87 machines. STACK OVERFLOW 4.00b You may get this problem when compiling with BC or BASCOM 6. This is a compiler bug, not an error in your program. Contact MS at 206-454-2030 if you have this problem. STATIC QB 4/BC7 When used with a subprogram, makes the subprogram faster, since local variables are not initialized on each call. STR$(Value) QB 4* Considerably slower than in QB 3. See benchmarks in sample program #7. String Formula Too Complex QB 2/3 These compilers have a 19 item limit on string concatenation. If you have more than 19 variables/literals, you get a "String formula too complex" error. (89/03/31) String Space QB 4/QBX Drops you out to DOS without saving Corrupt your program. The solution is to save often! STRING$ All A$=String$(5,65) takes less code than A$=String$(5,"A") and both are smaller than A$="AAAAA". SUB...END SUB QB 4/BC7 Cannot be used in $INCLUDE files. Cannot have the same name as a variable (regardless of the variable type). SWAP QB4/QBX Swapping *portions* of a user-defined type in the environment can cause a crash during binding. Swapping the *entire record* will not cause a crash. (89/12/22) SWAP of single precision array elements with BC7 BC 7 See sample program #39. (90/07/30) SWAP with CONST QB 4.50 See sample program #35. (89/09/07) TAB with REDIM QB 4.50* See sample program #33. (89/04/24) TIMER Replacement The following is much faster than BASIC's TIMER function (90/08/27): MyTimer! = (PEEK(&H6C) + 256! * PEEK(&H6D)_ + 65535! * PEEK(&H6E)) / 18.206227! Too Many Files ??? A QB user has reported a problem that we are unable to duplicate. He says that the "Too many files" error can occur when a disk is full or there are too many files in the root directory. (89/02/10) Too Many Files 4.00b When you use QB to make an EXE program, if you get this error, it usually indicates that a module's complete file spec (i.e., drive, path and filename) is longer than 60 chars. 60 is the longest name that QB can handle. The solution is to shorten the file name. TYPE..END TYPE QB 4 There has been an unverified problem reported in QB when the record length is an odd number. A "FAR HEAP CORRUPT" error is generated. The problem does not seem to appear in BC, only QB. If you have an unusual, otherwise unexplained problem, try changing the record length to an even number. TYPE..END TYPE QB 4 See "DIM" for QB 4. TYPE..END TYPE (with COMMON) QB 4 See COMMON (with TYPE) and sample program #1. UBOUND QB 2-3 If you ERASE an array, UBOUND will return the upper bound of the array BEFORE it was erased. This works OK in QB 4. UNLOCK QB 4 See LOCK QB 4 (88/12/19) VAL QB 4 BC6/BC7 Much slower than QB3, including when /FPA switch is used. See part 2, under "VAL" for a workaround if you have Microsoft C. If you don't have C, you may want to consider MicroHelp's QB/Pro Volumes 1-4, which have routines that convert strings to integers and long integers. (90/01/08) VAL QB 4 BC6* Generates an error (rather than value of 0) when "e%" or "d%" (case doesn't matter) are the first characters in a string, or when "%" is the first character. (89/04/24) VAL QB 4* When you use VAL("&"), you get 203 instead of 0. WINDOW QB 2-4 Does not affect DRAW statements. ---------------------------------------------------------------------------- Part 2 - General points of interest ---------------------------------------------------------------------------- OPEN QB4.x BC7 When OPENing a file for APPEND and locking that file for write operations in a networking environment, you should be sure to specify an access clause of *both* read and write. If your access clause just specifies "write" it is possible that QB will return error 75 "Path/file access error" for the OPEN command. (90/03/03) ---------------------------------------------------------------------------- BC7 Type coercion from floating point to integer (90/06/19) The following program demonstrates a problem when coercing a floating point number to an integer in BC7. The program will work fine in the QBX environment, but returns spurious values for C% when compiled to an .EXE c2% = 10 a! = 1 DIM t%(10) FOR c% = 1 TO c2% PRINT c%, c2% t%(c%) = a! NEXT The perceived value of C% is not spurious, it is the value of C2%. A workaround: By not allowing automatic coercion to be the last operation in the loop, the perceived value of C% remains correct. The coercion in the VAL function also causes the same problem. c2% = 10 a! = 1 DIM t%(10) FOR c% = 1 TO c2% PRINT c%, c2% t%(c%) = a! i%=i%+1 ' Added dummy instruction NEXT ---------------------------------------------------------------------------- BC7 with Inboard/PC and CoProcessor (90/01/08) Effective with BC7, Microsoft has changed the way they test for the presence of a math coprocessor (80x87). They now test to see if the motherboard switch indicating a coprocessor is on or off. The Inboard/PC has to have the motherboard switch off. This means that BC7 won't recognize a coprocessor on such a system. ---------------------------------------------------------------------------- VAL Workaround (90/01/08) If you have Microsoft C, you can take advantage of two functions built into the C library that will speed up the VAL function when used with integers and long integers.. In your BASIC program, you need to declare two FUNCTIONs and you must work with ASCIIZ strings (a BASIC string with a CHR$(0) on the end): DECLARE FUNCTION ATOI% CDECL (BYVAL ST%) DECLARE FUNCTION ATOL& CDECL (BYVAL ST%) ST$ = "1" + CHR$(0) NUM% = ATOI%(SADD(ST$)) NUM& = ATOL&(SADD(ST$)) You'll also need to make a "dummy" C program, compile it and include it in your Quick Library (for use in the environment) and on the LINK command line: void dummy() int n; long l; char near *ST; n = atoi(st); l = atol(st) (90/01/18) Another suggestion from the same person is to read numeric DATA statements into strings and then use the ATOI function to get the integer value. ---------------------------------------------------------------------------- Converting large numbers to integers (89/12/22) (updated 90/10/07) A common technique to stuff a large number (between 32767 and 65536) into a BASIC integer is: BigNum& = 50000& Intg% = BigNum& + 65536 * (BigNum& > 32767) ---------------------------------------------------------------------------- Using CALL with literals takes lots of stack space. (89/10/10) ' Demonstrate the effect on stack space when using literals ' in CALL statements. ' First, run the program as is and note the low point for ' stack space. Then REM the line with variables in the CALL ' and unREM the line with literals and run the program again. ' Note that the low stack point is ten bytes lower when ' literals are used. In a large program with a lot of CALL ' statements, this can really add up. DEFINT A-Z PRINT "Lowest amount of stack space before CALL:"; FRE(-2) A% = 1 B% = 2 C% = 3 D% = 4 E% = 5 ' REM next line for second pass CALL TestStack(A%, B%, C%, D%, E%) ' UNREM next line for second pass 'CALL TestStack(1, 2, 3, 4, 5) PRINT "Lowest amount of stack space after CALL:"; FRE(-2) SUB TestStack (A%, B%, C%, D%, E%) END SUB ---------------------------------------------------------------------------- Long Integers in TYPE..END TYPE (BC 4.5*) When long integers are part of a user defined type, and used in a SUB, the results are unpredictable. If you compile the following, you'll get different results in BC4.5 with and without /O. TYPE BugRecord nbr AS LONG END TYPE CALL bugsub END SUB Bugsub DIM BUG(100) AS BugRecord BUG(1).nbr = 4 BUG(2).nbr = 6 PRINT BUG(1).nbr + BUG(2).nbr END SUB ---------------------------------------------------------------------------- BC 6 with math coprocessor (89/07/29) If you are using the Microsoft BASIC Compiler 6 (version 6.00 or 6.00b) and are using the default math library (/FPI), you may experience unexplained "overflow" errors if your program is running on a 286/386 with a math coprocessor AND under DOS 3.2 or 3.3. The solution is to use the alternate floating point math library (/FPA), however: If you are running on a machine with a math coprocessor, you're using Btrieve 4.x or 5.x, you've compiled with the /FPA switch, AND your program CHAINs, then you must perform a Btrieve "reset" (Op%=28) before CHAINing or an "illegal function call" error will result. ---------------------------------------------------------------------------- AB45ACVR.HLP and QB45ACVR.HLP (QB 4.50) The actual hypertext help file is QB45ACVR.HLP. Some of the entries in the help screens try to find AB45ACVR.HLP instead (i.e., the "Q" is changed to an "A". If you have a hard disk, you can remedy this by copying the "Q" file to the "A" file. (89/04/24) ---------------------------------------------------------------------------- BUILDRTM (BC7) Has a limit of 127 exports in a single extended runtime library. (89/04/24) Note that the error you receive is "Fixup overflow" when you run the BUILDRTM program. ---------------------------------------------------------------------------- BUILDRTM (BC7) Has a limit of 255 exports. (89/11/03) ---------------------------------------------------------------------------- Wyse PC Keyboard Problem Some early versions of the BIOS used by Wyse incorrectly set a byte in the BIOS data area that tells QB that an enhanced keyboard is present. This causes a lockup, since QB is using an "enhanced" BIOS call to read the keyboard and is not getting a response. ---------------------------------------------------------------------------- ATI EGA Wonder Cards If you find that you are unable to set EGA modes on a system with one of these cards, call ATI for a free BIOS upgrade. ---------------------------------------------------------------------------- Editor problem in QB 4.50 If the QB 4.50 editor seems to be "changing" your programs, including placing "garbage" characters on the screen, it may be due to your math "coprocessor" (80x87 chip). Two solutions: 1. Check to make sure that the coprocessor chip is firmly seated. 2. Make sure that the motherboard switch indicating the presence of the coprocessor is set correctly. ---------------------------------------------------------------------------- Keeping DTR High QB 4 According to Microsoft, you can keep DTR high when exiting from QB 4.x by performing the following steps: 1. Close the serial port. 2. Immediately perform one of the following statements: a. For COM1: OUT &H3FC,3 b. For COM2: OUT &H2FC,3 The OUT command will force pin 20 (DTR) to stay high. DTR will actually be dropped for an instant between the CLOSE and the OUT, but it should be too short for the modem to care. If this does cause a problem, try adjusting the "S" register (see your modem manual) to allow a larger time-out period before dropping the carrier. ---------------------------------------------------------------------------- Logitech Mouse Info QB 4.50 (88/12/19) When running QB 4.5, if DOS is in 25 line mode and the QB editor is started with the /h option for 43 line mode, a Logitech Hi-Rez Bus mouse cursor disappears below line 25. Solution: use the Microsoft vers. 6.24 mouse driver that came with QB4.5 or get the Logitech vers. 3.43 or later driver. Contact Logitech at 1-415-795-8500. Another solution is to use MODE43.COM from earlier QB versions to put the screen in 43 line mode before starting QB4.5. ---------------------------------------------------------------------------- Non-IBM EGA cards QB4.50 (88/12/19) After running a program that uses the 25 line mode and a return is made to the editor, press F4 to review the Output screen and then press any key to return to the editor. The screen will return to 43 line mode but the lines below line 25 will be blacked out. The problem was found to be the Tseng EVA-480 EGA card. A temporary fix is to do 'Alt-F' and then 'D' to execute a shell to DOS and immediately return or else press F5 to rerun the loaded program to restore the full 43 lines. The better solution is to just not use the F4 key until the Tseng card's rom is updated or QB is fixed. ---------------------------------------------------------------------------- Cut and Paste Problems QB 4.50 (88/12/19) On some "clone" computers, the Cut and Paste keys (Ctrl-Ins) and (Shift-Ins) do not work correctly. There are two things you can try: 1. Turn off Caps Lock, Num Lock and Scroll Lock. 2. Run FIXSHIFT.COM with the "/I" switch to force installation. If neither of the above work, contact Microsoft and let them know what your hardware configuration is. ---------------------------------------------------------------------------- Avoiding unwanted line feeds when printing to LPT When you LPRINT a CHR$(13), QB4 automatically appends a CHR$(10) character causing "unwanted" line feeds. To avoid this problem: OPEN "LPT1:BIN" FOR OUTPUT AS #1 Then instead of using LPRINT, use PRINT #1,String. This causes the output to the printer to be "unfiltered". ---------------------------------------------------------------------------- DOS 4.00 On August 29, 1988, Infoworld reported several known problems with IBM DOS 4.0. Their suggestions include: 1. If you use the DOS "Shell", run it in text mode to avoid conflicts with TSR programs. 2. Disk un-fragment programs, such as Norton Utilities, Mac Utilities, VOPT, etc. don't work. 3. Lotus Metro doesn't work. 4. Don't use the EMS driver that comes with DOS if you have a third-party memory board. Instead, use the driver that came with the board. 5. Don't try to install IBM DOS 4.0 on a hard disk that already has a non-IBM version of DOS 3.x. 6. Don't use the "/X" switch with any itmes in CONFIG.SYS. In the same issue, Cringely reports that IBM is working on DOS 4.1. ---------------------------------------------------------------------------- Problems when moving SUBs between modules in the environment. The following is unedited text uploaded by a Compuserve user. The problems described have not been confirmed - this is included for your info and so that you can avoid doing what he did. On SOME occations, QB will not let you save your program, giving instead an "Out of Memory" error. Automatically, you lose everything you've done since you last saved. But upon exiting, you also find that the file was erased from the disk! GONE! Using Norton can RARELY bring it back (usually trying to load the resurected file causes a complete system hang). This has happened at least 10 times to me. The program is VERY large (over 1200 lines) with many Subprograms. The most notable cause (but not ONLY) is when moving a SUBprogram from one program to another (i.e. copying it). When deleting the original SUB line in the target program and substituting the one to be copied (with <Sift><Ins>), everything appears fine until the next save. This does not always happen, but USUALLY. If I do not remove the original SUB line, it doesn't seem as likely to happen. These are all the clues I have on this one. Also, jumping between programs using <F>ile <O>pen tends to aggrivate the problem. If I do this frequently, a <F>ile <N>ew is likely to give me a "string space corrupt" or "far heap corrupt" error and dump me back to DOS. Remember, these are large programs, with large arrays (the /AH switch). ---------------------------------------------------------------------------- Embedded Ctrl Characters (QB 4*) Pressing Ctrl-P, followed by CHR$(12) (regardless of how you enter it), does not embed a CHR$(12) in the text. However, if you use another text editor to embed the CHR$(12), QB will display it just fine. ---------------------------------------------------------------------------- Using DECLARE (QB 4*) without a CALL The following code demonstrates a quirk after a SUB has been DECLAREd and you invoke it without a CALL: DECLARE SUB XSUB (A!) start=0 XSUB (start-1)\20+1 ' This does not work. QB cannot parse it. XSUB ((start - 1) \ 20 + 1) ' This works. Note that the entire ' expression is enclosed in parentheses. SUB XSUB(A!) A!=A!+1 END SUB ---------------------------------------------------------------------------- QB4 editor and marked blocks If you mark a block, using the SHIFT and cursor keys, and then you type a space (while still pressing the SHIFT key), your marked block will disappear. ---------------------------------------------------------------------------- Scan Codes for F11-F12 and Variations: F11=133 F12=134 Shift-F11=135 Shift-F12=136 Ctrl -F11=137 Ctrl -F12=138 Alt -F11=139 Alt -F12=140 ---------------------------------------------------------------------------- Long integers with QB 4* When you have a long integer array with two dimensions, BC may not handle the zeroth elements correctly on machines without a math coprocessor unless you use the "/d" switch. QB handles the situation OK because "debug" is always on when working in the environment. Secondly, if you dimension the same two-dimensional array using a variable name instead of a numeric constant, BC may not handle your array at all! The fix is to use only constant numbers in dimensioning the array. Another fix that DOES work with dynamic arrays, is to use the /R switch when compiling. ---------------------------------------------------------------------------- More on long integers * If you pass a long integer array to a subprogram, QB will work OK, but BC does not. See Sample Program #2. ---------------------------------------------------------------------------- Long Integers and Calculations QB 4 ` Calculations using long integers should be tested thoroughly after compilation with BC. Sample Program #6 demonstrates the problem. ---------------------------------------------------------------------------- LIB environment variable If you set the LIB environment variable, you will find that QB, BC, BUILDLIB and LINK will all search the specified path whenever a User Lib, Quick Lib or LINK lib is needed. The syntax is similar to the DOS Path syntax: SET LIB=C:\Libs;C:\DOS;C:\QB Note that this does not have any effect when you are compiling from within the QB4` environment, and QB sticks the name of a library in the object module field. ---------------------------------------------------------------------------- Undocumented switches in QuickBASIC 3 QB ProgramName/F compiles the specified program to an EXE file without starting up the QB editor. QB ProgramName/Z tells QB to load and execute ProgramName and exit to DOS when the program ends. ---------------------------------------------------------------------------- Response files BUILDLIB and LINK both accept input from response files. This is exactly the same as redirection of input, but the programs will continue running when the end of the file is reached prematurely. Example: Response file contains: Prog1+Prog2+Prog3+ Prog4+Prog5+Prog6 Rem Don't include ANY additional blank lines Buildlib batch file contains: Buildlib @Response.Fil,MyLib.Exe; Buildlib will take its input from the response file because the "@" sign tells it to! ---------------------------------------------------------------------------- BUILDLIB and "too many segments" error Where "nnnn" is a number from 1 to 1024, use: BUILDLIB /SEG:nnnn That increases (or decreases) the number of allowable segments. Default=255. ---------------------------------------------------------------------------- Entering unusual ASCII values. If you're not familiar with WordStar, you may not know that you can enter unusual characters into the QB4 editor by doing the following: Hold the Ctrl key and press "P" once (nothing will happen). Release the Ctrl key. Press and hold the Alt key. Using the keypad number keys (not the keys on the top of the keyboard), enter the ASCII value for the key you want. For example, the 'Esc' key is ASCII 27, so press the "2", then the "7". Release the Alt key, and your special character will appear! ---------------------------------------------------------------------------- Part 3 - Sample programs ---------------------------------------------------------------------------- Sample program #1. How to use COMMON with TYPE'd variables. ' Prog1.bas TYPE Namerec LastName AS STRING * 20 FirstName AS STRING *15 END TYPE COMMON Filename() AS Namerec DIM Filename(5) AS Namerec Filename(1).LastName="Novisoff" Filename(1).FirstName="Mark" CHAIN "Prog2" ' Prog2.bas TYPE Namerec LastName AS STRING * 20 FirstName AS STRING * 15 END TYPE COMMON Filename() AS Namerec PRINT Filename(1).LastName, Filename(1).FirstName ---------------------------------------------------------------------------- Sample program #2. Demonstrates problem with long integers in subprograms. DECLARE SUB TestLong (LongArray&()) 'Demonstration to show difference between return values of long integers 'Returns desired value if compiled in the environment, but not if compiled 'by BC. 'This fault only appears if the code is in a subprogram and compiled with BC REM $Dynamic DIM LongArray&(10) DIM MainArray%(10) CLS LongArray&(1) = 100 MainArray%(1) = 10 FOR x% = 1 TO 2 LongArray&(1) = MainArray%(1) + LongArray&(1) ' Note: if you change the above into the following two lines, this part ' of the program will run correctly. 'Temp& = MainArray%(1) 'LongArray&(1) = Temp& + LongArray&(1) NEXT PRINT "TestLong should = 120" PRINT "Long Array from MAIN = "; LongArray&(1) PRINT : PRINT "Same code in a subprogram" PRINT CALL TestLong(LongArray&()) PRINT "TestLong should return 120" PRINT "Long Array from TestLong sub = "; LongArray&(1) SUB TestLong (LongArray&()) DIM IntArray%(10) LongArray&(1) = 100 IntArray%(1) = 10 FOR x% = 1 TO 2 LongArray&(1) = IntArray%(1) + LongArray&(1) ' Note: if you change the above into the following two lines, this part ' of the program will run correctly. 'Temp& = IntArray%(1) 'LongArray&(1) = Temp& + LongArray&(1) NEXT END SUB ---------------------------------------------------------------------------- Sample program #3. Demonstrates problem with PAINT in QBX and BC7 when chr$(0) is used. ' This code erases the yellow line in earlier compilers, ' but QBX/BC7 can't handle the CHR$(0) in the PAINT statement. SCREEN 8 LINE (0,0)-(150,150),15,B LINE -(0,0),14 PAINT (1,1),chr$(0),15 ---------------------------------------------------------------------------- Sample program #4. Demonstrates the limit on dynamic numeric arrays in QB 3. This program generates a program called ARRAY.BAS. Compile ARRAY.BAS with the "/d" switch, LINK it and RUN it. The sole function of ARRAY.BAS is to generate arrays. Regardless of the value of I%, and regardless if you use "#", "%" or "!" as the array type, the program gives an "Out of memory" error when the 124th array is DIMmed. OPEN "O",#1,"ARRAY.BAS" PRINT #1,"I%=1" FOR J=1 TO 126 L=L+10:PRINT #1,MID$(STR$(L),2);" DIM A";MID$(STR$(J),2);"#(I%):PRINT FRE(-1)" NEXT CLOSE END ---------------------------------------------------------------------------- Sample program #5. Demonstrates the a problem with PRINT TAB(x) followed by PRINT USING in QB4.50. Fixed in MS PDS 7.0. The program works OK in the QB4.50 environment. However, if you use BC 4.50 to compile and LINK this program, you'll get strange results. The workaround is to REM the PRINT TAB statements and UNREM the LOCATE statements. CLS OPTION BASE 1 DEFINT C, I C = 2 DIM N$(C) DIM B(C) FOR I = 1 TO 2 'Generate data N$(I) = CHR$(64 + I) 'Row labels array B(I) = .08 * (I) ^ 4 'Arbitrary array of numbers to print NEXT I PRINT TAB(5); "Char" FOR I = 1 TO 2 PRINT TAB(5); N$(I); PRINT TAB(10); B(I); PRINT TAB(23); 'LOCATE , 23 PRINT USING "###.####"; B(I); PRINT TAB(40); 'LOCATE , 40 PRINT USING "###.###"; B(I); PRINT TAB(60); 'LOCATE , 60 PRINT USING "####.##"; B(I) NEXT I END ---------------------------------------------------------------------------- Sample program #6. Demonstrates long integer calculation problem. This program will run in QB 4.00 and 4.00a, but it gives incorrect results using BC or BC 6. This problem has been fixed in the BC that comes with QB 4.50. DEFINT J: DEFLNG T DIM tum(2), ttm(2), th(2) ttm(2) = 100000: th(2) = 1000000: j = 2 PRINT th(j) * VAL("9") + ttm(j) * VAL("9") ' Result should be "9900000" ' Substituting th(2) for th(j) (etc). makes it work. So does using ' CLNG(VAL("9")). It also works when the array tum(2) isn't there. ' Compiling with "/d" may fix the problem in some cases. Substituting ' a single precision number seems to work. ---------------------------------------------------------------------------- Sample program #7. Demonstrates slowdown in STR$ function in QB 4. defint a-z a!=timer for n=1 to 5000 a$=str$(n) next print "elapsed:" timer-a! ---------------------------------------------------------------------------- Sample program #9. Demonstrates a problem with IF..THEN..ELSE. Using any compiler except QB4.00 and QB4.00a, the string "THIS IS AN ERROR" is never printed. Using these two environments causes the string to print whenever X<>2. 10 INPUT "TYPE A NUMBER ", X 20 IF X = 2 THEN 50 : PRINT "THIS IS AN ERROR" 30 PRINT "AT LINE 30" 40 GOTO 10 50 PRINT "AT LINE 50" 60 GOTO 10 ---------------------------------------------------------------------------- Sample program #10. Demonstrates a problem when INPUT is used directly to an array element that is beyond the maximum dimension of the array. When run inside the QB 4 environment, this program will cause a hard crash. This problem does not apply to LINE INPUT. This problem has been fixed in QB 4.50. DIM A$(20) FOR I = 1 TO 20 A$(I) = STR$(I) NEXT INPUT "Enter something: ", A$(I) ' At this point, I=21 ---------------------------------------------------------------------------- Sample program #11. Demonstrates a problem with REDIM PRESERVE in BC 7.10 ' This program works when compiled with /FS/O/AH. It gives ' "out of string space" error when compiled with /O/AH (near strings) DEFINT A-Z FOR N = 1 TO 32766 STEP 16 IF INKEY$ = CHR$(27) THEN STOP REDIM PRESERVE X(N) AS STRING * 64 LOCATE 25, 1 PRINT N, FRE(""), FRE(-1); NEXT ---------------------------------------------------------------------------- Sample program #12. Demonstrates a problem with Instant Watch in QB 4.50 Run this program in QB4.50. When it stops, put your cursor under the "A" in A$ and press Shift-F9 and then <Enter>. Your system will crash. The workaround is to either use Alt-D-<Enter> and type in the name of the string, or to put A$ in the watch window before it is assigned characters. The problem has been fixed as of QBX in PDS 7.1. A$ = STRING$(200, 65) STOP ---------------------------------------------------------------------------- Sample program #17. Demonstrates a problem using GOTO inside an IF..THEN..ELSE block. This program will work fine in the QB4.00 and QB4.00a environment, but will fail when compiled with BC or BASCOM 6. By "fail", I mean that both PRINT statements are executed. The problem has been fixed in the BC that comes with QB 4.50. x% = 1 IF x% = x% THEN PRINT "1 equals 1" GOTO 10 10 x% = x% ELSE PRINT "1 does not equal 1" END IF ---------------------------------------------------------------------------- Sample program #18. Demonstrates a problem using /S in conjunction with /O and communications, where a string literal (in quotes) is used for the COM parameters. This problem has been fixed in the BC that comes with QB 4.50. ' compile with BC: ' BC prog/s/o; (produces device unavailable error but runs ' fine in the environment) ' and ' BC prog/o; (runs fine) CLS OPEN "COM1:1200,O,7,1,CS,DS,CD" FOR RANDOM AS #1 LEN = 256 PRINT #1, "ATM1X2E1 S11=72DT 999-9999;" PRINT "Press any key to continue..." DO WHILE LEN(INKEY$) = 0: LOOP PRINT #1, "ATH" CLOSE END The solution to the above is to assign the COM specifications to a string before doing the OPEN: A$ = "COM1:1200,O,7,1,CS,DS,CD" OPEN A$ FOR RANDOM AS #1 LEN = 256 ---------------------------------------------------------------------------- Sample program #19. Demonstrates a problem where If a breakpoint is set on a CASE line of a SELECT CASE ... END SELECT statement, the SELECT CASE structure is not executed properly. QB 4.50 tells you that you cannot set a breakpoint on a CASE or END SELECT statement. Some fix!!! 'Set a breakpoint (F9) on the 'CASE 1' line, and RUN the program (F5) DEFINT A-Z A = 2 SELECT CASE A CASE 1 PRINT "A equals 1" CASE 2 PRINT "A equals 2" CASE ELSE PRINT "A is not equal to 1 or 2" END SELECT ---------------------------------------------------------------------------- Sample program #21. Demonstrates a problem with PUT and QB4.00b OPEN "test.dat" FOR RANDOM AS 1 LEN = 140 t$ = STRING$(140, "A") LSET buffer$ = t$ PUT #1, , t$ CLOSE 1 This program will work with QB4.00a but not with QB4.00b The solution is to use the "old-style" FIELD statement: OPEN "test.dat" FOR RANDOM AS 1 LEN = 140 FIELD 1,140 as Buffer$ LSET Buffer$ = STRING$(140, "A") PUT #1,1 CLOSE 1 The following info was added 89/10/07 (contributed by Phil Weber): The reason for this is that, beginning with version 4.00b, when PUTting a variable-length string into a RANDOM file, QB precedes the string with its length (a two-byte integer). Thus the (apparently) 140-byte T$ above becomes 142 bytes in length. Your recommended solution is to declare a file buffer using the FIELD statement -- that works because FIELDed strings are not variable-length. Two other options are to declare the record length two bytes longer than you actually need (albeit a bit wasteful, but it works!), or to DIM your string variable to a fixed length, like this: OPEN "Test.Dat" FOR RANDOM AS #1 LEN = 140 REDIM T AS STRING * 140 T = STRING$(140, 32) PUT 1, , T CLOSE Thought the above info might help anyone who's been perplexed by the "Bad Record Length" error. ---------------------------------------------------------------------------- Sample program #22. Demonstrates a problem with CALL: Note that this program requires TEST.DAT, which is part of the ARC file. It also requires that you use an assembly subroutine to display a string from the array. The fix is to place A$() in a COMMON SHARED statement and take it out of the parameter list in the CALL and the SUB statements. DEFINT A - Z DIM A$(3) CLS OPEN "R", 1, "TEST.DAT", 128 FIELD 1, 32 AS A$(1), 6 AS A$(2), 90 AS A$(3) PRINT "Getting Record One" GET 1, 1 PRINT "A$(1) Contains: "; A$(1) PRINT "A$(2) Contains: "; A$(2) CALL AnotherWay (A$()) PRINT PRINT "Getting Record Two" GET 1, 2 PRINT "A$(1) Contains: "; A$(1) PRINT "A$(2) Contains: "; A$(2) CALL AnotherWay (A$()) CLOSE END SUB AnotherWay (A$()) STATIC stop ' Insert a call to an assembler routine to display A$(1) ' The following 2 lines are included for the benefit of Mach 2 users. ' R%=CSRLIN:C%=POS(0) ' CALL MhScr(A$(1),0%,R%,C%,7%) PRINT PRINT A$(2) END SUB ---------------------------------------------------------------------------- Sample program #23. Demonstrates a problem with SHARED in QB4.00b. The problem did not exist in QB4.00. If you change the name of db to something else, or you place db and db() in the parameter list, all is well. The problem seems to be that if you have a scalar with the same name as an array, and you name it in the SHARED statement, QB thinks that the scalar and the array are one in the same. DIM db(10) db(1) = 1 db = 2 CALL Test(db) SUB Test (db) SHARED db() '<= duplicate definition error PRINT db, db(1) END SUB ---------------------------------------------------------------------------- Sample program #24. Demonstrates a problem with '$Include in all versions of QB 4.00x: ' Load this program into QB, move the cursor to the end of the first ' rem $include line and press the Del key. You will get "string space ' corrupt" and when you go to run another program, you are hung! REM $INCLUDE: 'c:\subprogs\done\ssinput.cal' REM $INCLUDE: 'c:\subprogs\done\vinput.cal' ---------------------------------------------------------------------------- Sample program #25. Demonstrates a problem with long integers used in user defined types. When you attempt to compile the following program with BC, you'll get an "Internal error" message from the compiler. The problem has been fixed in the BC that is included with QB4.50. DEFINT A-Z TYPE Bt a AS INTEGER b AS LONG c AS LONG END TYPE DIM Bt(1) AS Bt Bt(y).b = x& Bt(y).c = Bt(y).b There are several ways of "fixing" the above: 1. Swap the last two lines. 2. Change a variable subscript (y) to literal subscript (1) 3. Change the order of the variables a,b,c. 4. Add a line between the last two lines, like "j=k*3" 5. Break the last line up into: temp&=Bt(y).b Bt(y).c=temp& The problem apparently has to do with optimization of the last two lines of code. ---------------------------------------------------------------------------- Sample program #26. Demonstrates a problem with FRE(-2) in all versions of QuickBASIC 2-4. DEFINT A-Z PRINT "before call", FRE(-2) CALL test PRINT "after call", FRE(-2) ' For QB2/3, add the STATIC keyword after SUB test SUB test PRINT "entering sub", FRE(-2) REDIM a$(100) FOR i = 0 TO 100 a$(i) = "this is a test" NEXT i PRINT "before erase", FRE(-2) ERASE a$ PRINT "after erase", FRE(-2) END SUB ---------------------------------------------------------------------------- Sample program #28. Demonstrates a problem with periods in variable names. ' Note - name this program TEST1.BAS DEFINT A-Z DIM STG$(10), DBLP#(10), INTG(10) COMMON SHARED STG$(), DBLP#(), INTG(), message$ message$ = "Hello there." CHAIN "TEST2" ' Note - name this program TEST2.BAS DEFINT A-Z DIM STG$(10), DBLP#(10), INTG(10) COMMON SHARED STG$(), DBLP#(), INTG(), message$ DIM er.Mem(1024) 'Bad Guy TYPE item store AS STRING * 1 item AS STRING * 5 END TYPE DIM itemrec AS item 'Contributor to the problem PRINT "OK, This is the message... "; message$ END Note that the error occurs in QB 4.00b and QB 4.50. The second DIM in TEST2.BAS combined with the DIM of an array with a period, causes the problem. ---------------------------------------------------------------------------- Sample program #29. Demonstrates a problem with INT in all versions of QB 4 and QBX. (88/12/19). 'This bug only happens using BC4.50/7.0 and QB4.50/QBX. It works 'fine in the environment using earlier versions of QB4. 'The INT(numeric expression) statement does not always return the 'correct value if the numeric expression is a calculation. The 'following example will illustrate: A = .9 B = 10 C = INT(A * B) 'This will produce a result of 8 instead of 9. PRINT "All numbers shown should be 9" PRINT C D = A * B PRINT D C = INT(D) 'This will produce the correct result. PRINT C C = INT(.9 * 10) 'This will also produce the correct result. PRINT C ---------------------------------------------------------------------------- Sample program #30. Demonstrates a problem with CINT in all versions of QB 4. (88/01/03) FOR I = -10.5 TO 10.5 PRINT I, CINT(I) NEXT ---------------------------------------------------------------------------- Sample program #31. Demonstrates two problems when you LINK with /PAC. (89/02/10) If you use the /PAC switch, strange things can happen to your programs. Compile the code shown below into two object modules using the /X switch. ' This is TEST1.BAS CALL Test2 DATA "This is string 1" DATA "This is string 2" ' This is TEST2.BAS Ehandler: RESUME NEXT Test2Data: DATA "This is string 3" DATA "This is string 4" SUB Test2 ON ERROR GOTO Ehandler RESTORE Test2Data READ A$ PRINT A$ READ A$ PRINT A$ PRINT "Error was handled ok." END SUB If you LINK the programs normally, the strings are printed correctly and the error is handled properly. If you LINK the same modules with /PAC, the data are not read and the error is not handled! ---------------------------------------------------------------------------- Sample program #32. Demonstrates a problem with DECLARE. (89/02/10) In the following program, "MySub1" is not executed. Instead, QB treats the invocation of the SUB as a label. Note that this happens only when there are no parameters, and you omit the CALL keyword (requiring that you DECLARE the procedure). In addition, there must obviously be a colon on the line after the name of the SUB. DECLARE SUB MySub1 () DECLARE SUB MySub2 () MySub1: MySub2 SUB MySub1 PRINT "Hello" END SUB SUB MySub2 PRINT "Goodbye" END SUB ---------------------------------------------------------------------------- Sample program #33. Demonstrates a problem using TAB with REDIM in QB 4.50. (89/04/24) REDIM Text$(4) Text$(1) = "1111" PRINT TAB(4); Text$(1); Remove the TAB(4); or change REDIM to DIM and it'll work. As it sits it bombs the computer requiring a reboot. Variables vs literals in the TAB argument don't appear to affect it after all. This affects both PRINT and LPRINT. ---------------------------------------------------------------------------- Sample program #34. Demonstrates a problem using DATA, READ and RUN with BC4.00b and BC6.00b (89/07/29) ' On the second and subsequent executions of this program, BC4.00b gives ' a SYNTAX error, while BC6.00b just prints zeros. READ A% PRINT A% IF INKEY$ <> "" THEN END RUN DATA 1 ---------------------------------------------------------------------------- Sample program #35. Demonstrates a problem using SWAP and CONST in QB 4.50 (89/09/07) ** Warning - this program will crash your system ** Load the following program into QB4.50 and press F5: const Nul$="" z$="hello" swap z$,Nul$ QB4.50 gives different results, depending on if Nul$ is "" or has a length. QB4.00b and QBX correctly trap the error of trying to SWAP a constant. ---------------------------------------------------------------------------- Sample program #36. Demonstrates a problem using temporary strings with DEF FN in all compilers. When a string is passed as an argument to a DEF FN function, it remains in memory until the next time that function is invoked. In (almost) all other situations where BC/QB has to create a temporary string, it calls the "String Delete" routine to mark it as free for the garbage collection. So if you pass, say, a 10K string as an argument, you just lost 10K of string space. Ouch, no? This happens only when compiled to disk though, not in the environment. Proof follows. DEF FNOuch% (Work$) X = LEN(Work$) END DEF PRINT FRE("") Dummy = FNOuch%(STRING$(10000, "A")) PRINT FRE("") ---------------------------------------------------------------------------- Sample program #37. Demonstrates a problem with INSTR in BC 4.x DEFINT A-Z CLS Literal$ ="" 'This string is made in the QB Editor by 'typing Ctrl-P and then holding down Alt 'while typing ASCII code of character. 'Enter ASCII 1 through 5. FOR I = 1 TO 5 Found = INSTR(Literal$, CHR$(I)) PRINT "INSTR reports CHR$("; MID$(STR$(I), 2); PRINT ") at position"; Found; "of Literal$." NEXT PRINT Char$ = CHR$(1) + CHR$(2) + CHR$(3) + CHR$(4) + CHR$(5) FOR I = 1 TO 5 Found = INSTR(Char$, CHR$(I)) PRINT "INSTR reports CHR$("; MID$(STR$(I), 2); PRINT ") at position"; Found; "of Char$." NEXT END In the environment, as one would expect, the above program reports CHR$(1) at position 1, CHR$(2) at position 2, etc. for *both* strings. But compiled to an EXE file, INSTR reports position 0 for CHR$(1) and CHR$(2) in Literal$ Note: BC7 documents that you cannot use CHR$(1) and CHR$(2) in a string. Actually, you can have those characters in a string, but INSTR and possibly PRINT won't work correctly. ---------------------------------------------------------------------------- Sample program #38. Demonstrates a problem with LINE (filled box) and VIEW that was not fixed until BC7. SCREEN 9 VIEW (1,1)-(150,150) LINE (-50,50)-(-100,100),12,B LINE INPUT "Image clipped correctly";Z$ LINE (-50,50)-(-100,100),12,BF LINE INPUT "Image *not* clipped correctly";Z$ ---------------------------------------------------------------------------- Sample program #39. Demonstrates a problem with SWAP and single precision array elements using BC7. DIM dt!(2), rn%(2) n = 1 a! = dt!(n) * 100000! + rn%(n) b! = dt!(n + 1) * 100000! + rn%(n + 1) SWAP dt!(n), dt!(n + 1) The above program gives an "out of memory" error. Remming the "+ rn%(.." in two places solves the problem. Microsoft suggests a SUB to do the SWAP: CALL SwapSub(DT!(n), DT!(n+1) SUB SwapSub(A!, B!) SWAP A!, B! END SUB ---------------------------------------------------------------------------- Part 4 - Video adapters compatible with QB 4.50 ---------------------------------------------------------------------------- The following cards are available "in-house" at Microsoft and were tested with QB4.50 Cards that PASSED: (Note - if the card is a VGA but not an IBM PS/2 VGA, there will be problems swapping on screen 10.) AST EGA (256k) Compaq Portable (Monochrome) Compaq VGC (Their name for VGA) Daewoo (Leading Edge/AT) EGA (256k) Monochrome Genoa EGA (256k) Genoa EGA (256k) monochrome Hercules Monochrome IBM EGA 256k IBM EGA 64k IBM PC Convertible IBM VGA (Non-PS/2) IBM PS/2 VGA IBM MCGA IBM EGA (64k) with monochrome IBM CGA IBM MDPA NCR EGA Olivetti Monochrome Olivetti EGA (256k) Olivetti VGA Paradise Autoswitch EGA (256k) PC's Limited VGA Tandy EGA (256k) Vega Video-7 Deluxe EGA (256k) Zenith EGA monochrome ________________________________________________________________________ Cards that loaded QB, but had numerous problems with screen swapping Techmar VGA Quadram VGA Vega-Video 7 Fastwrite VGA Vega VGA ________________________________________________________________________ Cards not guarenteed to load QB (cards in this section would not load QB, but may) Compaq Laptop (BIOS problem - no fix) Genoa SuperVGA HiRes (models 5100 and 5200) VIP ATi VGA Sigma EGA! ________________________________________________________________________ In addition, these cards have been reported by support as potential problem cards. Older Quadram CGA adapters Sperry Hercules compatible and CGA adapters (stock in Sperry machines) Leading Edge CGA and Hercules compatible adapters (stock in Leading Edge Model M machines) ________________________________________________________________________ {End of QUIRKS.TXT file}