Re: shorts and longs

"Lance" <nunya@xxxxxxxxxxxx> wrote in message
news:ejvfy8fkFHA.2916@xxxxxxxxxxxxxxxxxxxx
> it was my understanding that a c type short was equal to a vb type
> integer, and a c type long was equal to a vb type long.

....c type "int" is the same as a VB type long

> according to the tif file specs, the compression tag (259) stores
> it's value (either 1, 2, 3, 4, 5, 6, or 32773) as a short type (a vb
> integer) but as you can see, one of the valid values of the
> compression type is 32773, which is out of the range of a vb integer.
> so, when i Dim m_Compression as Integer and the return value is
> 32773, i get an overflow obviously. i can change it to Dim
> m_Compression as Long, but will that cause any trouble i'm not aware
> of?

32773 is valid for an unsigned 16-bit value; it is not valid for a signed
16-bit value and unfortunately VB only supports signed values. If you read
the 16-bit value from a file into an Integer variable you will get a
negative number (-32763) which is fine since it will have the same bit
pattern as +32773 so it is essentially equivalent. If you are calling a
function that returns a 16-bit value then it should also work but if you
call a function that returns a 32-bit value then VB will complain about not
being able to convert to Integer because it will be outside the range. You
can accept that value into a VB Long to avoid the error and then mask off
the lower 16 bits but how you handle it will depend on what the exact
situation is. What are you calling that is giving you the return value and
how is that function defined?

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