How DEFINT, DEFSNG, DEFDBL Affect Type of DEF FN Function (21311)

SUMMARY

This article discusses the default type declaration of DEF FN user-defined functions in Microsoft Basic.

The DEFINT, DEFLNG, DEFDBL, and DEFSNG statements affect the first letter of the variable part of a DEF FN function name, and not the FN part of the function name. This information applies to all Microsoft Basic compilers and interpreters for MS-DOS, MS OS/2, Macintosh, and CP/M-80.

Microsoft Basic Compiler versions 6.00 and later, and QuickBasic versions 4.00 and later for the IBM PC, introduced the DEFLNG statement for long integer declaration, which also behaves this way.

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Example

The following program prints 1.2 (a noninteger):

   10 DEFINT F   ' DEFINT F doesn't affect the DEF FN below.
   20 DEF FNAB=1.2
   30 PRINT FNAB

The following program prints 1 (truncated to an integer):

   10 DEFINT A   ' DEFINT A does affect the DEF FN below.
   20 DEF FNAB=1.2
   30 PRINT FNAB