User manual
mikroBasic PRO for dsPIC30/33 and PIC24
MikroElektronika
223
Sizeof Operator
The prex unary operator sizeof returns an integer constant that represents the size of memory space (in bytes) used
by its operand (determined by its type, with some exceptions).
The operator sizeof can take either a type identier or an unary expression as an operand. You cannot use sizeof
with expressions of function type, incomplete types, parenthesized names of such types, or with lvalue that designates
a bit eld object.
Sizeof Applied to Expression
If applied to expression, the size of an operand is determined without evaluating the expression (and therefore without
side effects). The result of the operation will be the size of the type of the expression’s result.
Sizeof Applied to Type
If applied to a type identier, sizeof returns the size of the specied type. The unit for type size is sizeof(byte)
which is equivalent to one byte.
Thus:
sizeof(byte) ‘ returns 1
sizeof(integer) ‘ returns 2
sizeof(longword) ‘ returns 4
sizeof(oat) ‘ returns 4
When the operand is a non-parameter of array type, the result is the total number of bytes in the array (in other words,
an array name is not converted to a pointer type):
dim i, j as integer
samples as integer[7]
...
j = sizeof(samples[1]) ‘ j = sizeof(integer) = 2
i = sizeof(samples) ‘ i = 10*sizeof(integer) = 20
If the operand is a parameter declared as array type or function type, sizeof gives the size of the pointer. When
applied to structures, sizeof gives the total number of bytes, including any padding. The operator sizeof cannot be
applied to a function.