checking for block definition

Can anyone help me write the code to check for a specific block definition? I need a lisp that will check a drawing to see if a block has been defined. If the block hasnt been defined the routine must then create it. Any help would be greatly appreciated.

 

(if (not (tblsearch "block" "your block name"))
(make block here)
)
This will see if the block is within the drawings database
or
(if (not (ssget "x" (list (cons 0 "INSERT") (cons 2 "your block name"))))
(make block here)
)
This will test to see if the block is physically inserted into the drawing.

Hope this helps
Tim

 

I assume you don't need to have the block definition in the drawing except
to Insert it. In that case, you could simply have that block (drawing)
located somewhere in the support file search paths in Options, and plain old
Insert it. If the block is already defined, it will use the definition
that's in the drawing, and if it isn't, it will find the file and bring it
in. That saves you the considerable hassle of creating the thing via lisp,
and you don't need to check whether it's there already, or anything.

Kent Cooper, AIA

definition? I need a lisp that will check a drawing to see if a block has
been defined. If the block hasnt been defined the routine must then create
it. Any help would be greatly appreciated.

 

Thanks everybody, with your help I was able to get the lisp working the way I needed it to.

 

I assume you don't need to have the block definition in the drawing except

I agree. It wasn't really clear what the OP was after. Conversely, if there
is a reason that the block needed to be created programmatically, rather
than by inserting it, then you could just go ahead and do the entmake (or
whatever) without checking for the definition first. Entmake will either
create or update a block definition, so it doesn't matter whether it was
already defined.