Single-Line IF...THEN Label, "Syntax Error"; Requires GOTO (59758)


The information in this article applies to:

  • Microsoft QuickBASIC 2.0, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 2.01, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 3.0, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 4.0, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 4.0b, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 4.5, when used with:
    • the operating system: MS-DOS
  • Microsoft BASIC Compiler for MS-DOS and OS/2 6.0
  • Microsoft BASIC Compiler for MS-DOS and OS/2 6.0b
  • Microsoft Basic Professional Development System (PDS) for MS-DOS and MS OS/2 7.0
This article was previously published under Q59758

SUMMARY

A single-line IF statement of the form IF <cond> THEN <label> causes a "Syntax Error." In a single-line IF statement, you must use the GOTO statement to branch to a line label. This is different from the branching rule for line numbers, where the GOTO is optional.

This information applies to Microsoft QuickBASIC Versions 2.00, 2.01, 3.00, 4.00, 4.00b, and 4.50 for MS-DOS, to Microsoft BASIC Compiler Versions 6.00 and 6.00b for MS-DOS and OS/2, and to Microsoft BASIC Professional Development System (PDS) Version 7.00 for MS-DOS and MS OS/2.

MORE INFORMATION

The following is the single-line IF statement syntax. (It is taken from the QuickBASIC 4.50 QB Advisor online Help system): 
      IF booleanexpression THEN thenpart [ELSE elsepart]
The thenpart and the elsepart both have the following syntax:

{statements | [GOTO]linenumber | GOTO linelabel }

The following list describes the parts of the thenpart and elsepart syntax: 
      Part         Description
      ----         -----------

      statements   One or more BASIC statements, separated by colons

      linenumber   A valid BASIC program line number

      linelabel    A valid BASIC line label

A Related Issue in QuickBASIC for the Apple Macintosh

Note that QuickBASIC for the Apple Macintosh does not require the GOTO for a label in an IF statement. This prevents making an implicit CALL, as in the IF...THEN subname statement. For more information, query on the following words:

Macintosh and QuickBASIC and GOTO and implicit and subprogram and explicit

Code Example

The following code example causes a syntax error on the IF statement: 
   IF 1 = 1 THEN Label      'Should be: IF 1 = 1 THEN GOTO Label
   Label: PRINT "Made it!"
Modification Type:MinorLast Reviewed:1/8/2003
Keywords:KB59758
©2002 Microsoft Corporation. All rights reserved.