leIsLayerValid

leIsLayerValid( 
l_layerPurposePair
[ d_techFileId ]
) 
=> t / nil

Checks whether layer l_layerPurposePair is a valid layer. If d_techFileId is not specified, the current technology file is used.

l_layerPurposePair	Layer-purpose pair to be checked for validity.
d_techFileId	The database ID of the technology file that is checked.

`t`	The layer d_layerPurposePair is a valid layer.
`nil`	The layer d_layerPurposePair is not a valid layer.

Returns t if layer-purpose pair metal1 drawing in lib2 is a valid layer.

leIsLayerValid( list("metal1" "drawing") lib2 )