SizeOf
Returns the size of a variable or type in bytes.
The SizeOf operator returns an Integer value: the number of bytes taken up by a variable or DataType (including the data fields of a UDT).
When used with fixed-length strings (including fixed-length ZStrings and WStrings) it will return the number of bytes they use, and when used with variable-length strings, it will return the size of the string descriptor.
(it is equal to Len only when used with fixed-length strings of STRING*N type and this since fbc version 1.20.0)
If there is both a user defined type and a variable visible with the same name in the current scope, the user defined type takes precedence over the variable. To ensure that the SizeOf takes the variable instead of the user defined type, wrap the argument to SizeOf with parentheses to force it to be seen as an expression. For example Sizeof((variable)).
Note: When used with array names, SizeOf returns the size of the array dadatype, but not the total size of the array. This differs from its behavior in C, where arrays could only be a fixed size, and sizeof() would return the number of it used.
For clarity, it is recommended that you avoid this potential confusion, and use SizeOf on the array datatype doing SizeOf(Typeof(array)), rather than the array name only doing SizeOf(array).
Remark: When used with a dereferenced z/wstring pointer, SizeOf always returns the number of bytes taken up by one z/wstring character.
Syntax
Description
The SizeOf operator returns an Integer value: the number of bytes taken up by a variable or DataType (including the data fields of a UDT).
When used with fixed-length strings (including fixed-length ZStrings and WStrings) it will return the number of bytes they use, and when used with variable-length strings, it will return the size of the string descriptor.
(it is equal to Len only when used with fixed-length strings of STRING*N type and this since fbc version 1.20.0)
If there is both a user defined type and a variable visible with the same name in the current scope, the user defined type takes precedence over the variable. To ensure that the SizeOf takes the variable instead of the user defined type, wrap the argument to SizeOf with parentheses to force it to be seen as an expression. For example Sizeof((variable)).
Note: When used with array names, SizeOf returns the size of the array dadatype, but not the total size of the array. This differs from its behavior in C, where arrays could only be a fixed size, and sizeof() would return the number of it used.
For clarity, it is recommended that you avoid this potential confusion, and use SizeOf on the array datatype doing SizeOf(Typeof(array)), rather than the array name only doing SizeOf(array).
Remark: When used with a dereferenced z/wstring pointer, SizeOf always returns the number of bytes taken up by one z/wstring character.
Example
Print SizeOf(Byte) ' returns 1
Type bar
a As Integer
b As Double
End Type
Dim foo As bar
Print SizeOf(foo)
a As Integer
b As Double
End Type
Dim foo As bar
Print SizeOf(foo)
Version
- Before fbc 1.08.0:
SizeOf was not returning the size of the data fields of a UDT.
When a variable from a given namespace was accessed with the namespace's name prefix, the argument to SizeOf had to be wrapped with parentheses to force it to be seen as an expression. For example Sizeof((namespace_name.variable)).
When a variable from a given namespace was accessed with the namespace's name prefix, the argument to SizeOf had to be wrapped with parentheses to force it to be seen as an expression. For example Sizeof((namespace_name.variable)).
Dialect Differences
- Not available in the -lang qb dialect unless referenced with the alias __Sizeof.
Differences from QB
- New to FreeBASIC
See also