Bookshelf v8.0: Visual Basic (VB) Variant Data Type

The variant data type can be used to define variables that contain any type of data. A tag is stored with the variant data to identify the type of data that it currently contains. You can examine the tag by using the VarType function.

Table 4. Variant Value Types
Type/Name	Size of Data	Range
0 (Empty)	0	N/A
1 Null	0	N/A
2 Integer	2 bytes (short)	-32768 to 32767
3 Long	4 bytes (long)	-2.147E9 to 2.147E9
4 Single	4 bytes (float)	-3.402E38 to -1.401E-45 (negative) 1.401E-45 to 3.402E38 (positive)
5 Double	8 bytes (double)	-1.797E308 to -4.94E-324 (negative) 4.94E-324 to 1.797E308 (positive)
6 Currency	8 bytes (fixed)	-9.223E14 to 9.223E14
7 Date	8 bytes (double)	Jan 1st, 100 to Dec 31st, 9999
8 String	up to 2GB	Length is limited by the amount of random access memory, up to 2 GB
9 Object	N/A	N/A

A newly defined Variant defaults to being of Empty type to signify that it contains no initialized data. An Empty Variant is converted to zero when used in a numeric expression, or to an empty string when used in a string expression. To test whether a variant is uninitialized (empty), use the IsEmpty function.

Null variants have no associated data and serve only to represent invalid or ambiguous results. You can test whether a variant contains a null value with the IsNull function. Null is not the same as Empty, which indicates that a variant has not yet been initialized.