Q58608: Bad EXE Result Assigning n Between 2 Statements Using Same n
Article: Q58608 Product(s): See article Version(s): 7.00 | 7.00 Operating System(s): MS-DOS | OS/2 Keyword(s): ENDUSER | SR# S900207-44 buglist7.00 fixlist7.10 | mspl13_basic Last Modified: 6-SEP-1990 Assigning a SINGLE-precision variable in a statement between two other statements that use that same variable can produce incorrect results in an .EXE compiled with BC.EXE in Microsoft BASIC Professional Development System (PDS) version 7.00 for MS-DOS and OS/2. This problem does not occur in the QBX.EXE (QuickBASIC Extended) environment. This error does not occur with the INTEGER, LONG, DOUBLE, or CURRENCY data types. Microsoft has confirmed this to be a problem in Microsoft BASIC PDS version 7.00. This problem was corrected in version 7.10. To work around this problem in 7.00, do ONE of the following: 1. Use the BC /X compiler option. 2. Make an assignment to a temporary variable before the second or third statement. 3. Place a line number or label on the second or third statement. 4. Place a DEFxxx statement in the program (such as DEFDBL A-Z), or explicitly DIMension the variable to be some data type other than SINGLE precision. This problem does NOT occur in Microsoft BASIC Compiler version 6.00 or 6.00b for MS-DOS and OS/2, or in Microsoft QuickBASIC version 4.00, 4.00b, or 4.50 for MS-DOS. The following code example illustrates the problem and contains workarounds #2 and #3 in comments: init = p 'temp = init 'Uncomment this line for workaround #2 'label: 'Uncomment this line for workaround #3 p = 200 wrong = p PRINT wrong, p 'In EXE compiled without /X, this prints 0 and 200
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