Обсуждение: column size in libpq

How to determinate column size in query in libpq? Especially when column
is declared for exapmle as varchar(64).  PQfsize return -1 which mean
that is variable and PQfmod returns 68.

Piotr Filipczuk

On Apr 25, 2005, at 4:53 AM, Piotr Filipczuk wrote:

> How to determinate column size in query in libpq? Especially when
> column is declared for exapmle as varchar(64).  PQfsize return -1
> which mean that is variable and PQfmod returns 68.

68 - 4 is the correct size for varchar(64). There is 4 bytes of
overhead included in the return value.

If you are trying to do something like column formatting where you need
to know the longest length, maybe take a look at the psql source and
see how it works there.



John DeSoi, Ph.D.
http://pgedit.com/
Power Tools for PostgreSQL