I'm not sure what you mean by 'ambiguous' or 'dynamic single layer'. There are
only a dozen functions in 'sdetype.h' that take SE_ENVELOPE parameters, and the
only functions that are relevant are the ones with "layer" in their name. From the
ArcSDE API standpoint, all layers are "single", and the only "dynamic" objects in the
API are the "shape table" and "point table" (SE_STABLE & SE_PTABLE) constructs,
neither of which are a "layer".
From an ArcSDE standpoint, you'll get much better performance if you aways initialize
all layers with their potential extent at creation time (e.g. set to "-180,-90,180,90" for
GCS_WGS_1984), which obviates the need to ever recalculate extents, from the API
*or* with 'sdelayer'.
- V